For developers
Engineers who write, review and ship application code.
Application security
59 guidesFix SQL injection in Python sqlite3
Bind query values separately from SQL syntax, then prove the fix preserves legitimate behavior and blocks an injection probe.
Development · Developers, AppSec engineers
Enforce authorization for every object action
Authorize the authenticated subject, requested operation, and specific resource together; a valid login or unpredictable identifier is insufficient.
Development, Testing · Developers
Design a safer file-upload pipeline
Treat upload receipt, content processing, storage, and later delivery as separate security decisions.
Design, Development · Developers, AppSec engineers
Verify webhook deliveries before acting
Verify the provider’s signature over the correct bytes, then apply replay, authorization, and idempotency controls before a business action.
Design, Development · Developers, AppSec engineers
Review tenant boundaries before implementation
Trace tenant identity through requests, data stores, caches, jobs, and administration, then turn plausible isolation failures into tests.
Design · Developers, AppSec engineers
Review trust boundaries in mobile and native clients
Protect local data and platform interactions while keeping server-side authorization independent of the client’s behavior.
Design, Development · Developers, AppSec engineers
Prevent XSS at the output boundary
Choose text rendering, context-aware encoding, or deliberate HTML sanitization according to how the browser will interpret the value.
Development · Developers
Constrain server-side fetches to their intended destinations
Prevent untrusted URLs from turning a preview, import, or webhook feature into access to internal services.
Design, Development · Developers, AppSec engineers
Handle failures without leaking internals or weakening controls
Give callers a useful, bounded response while preserving protected diagnostic evidence and safe application state.
Development · Developers, AppSec engineers
Ship without debug modes, verbose errors or exposed files
Turn off debug output, publish an allowlisted build and probe each deployment for exposed files and endpoints.
Development · Developers, Platform engineers and SREs
Run coordinated vulnerability disclosure from report to advisory
Make private reporting discoverable, verify reports, coordinate a tested remedy, and give affected users enough information to act.
Maintenance · Developers, AppSec engineers, Security leaders
Protect cookie-authenticated actions against CSRF
Make the server distinguish an intended action from a request another site caused the browser to send.
Development · Developers, AppSec engineers
Configure CORS and CSP around the browser capabilities you need
Control who can read API responses and which resources a page may execute without confusing either control with authorization.
Development · Developers, AppSec engineers
Render rich text without granting it application privileges
Choose text rendering or a restricted HTML policy, then test the final DOM after every transformation.
Development · Developers, AppSec engineers
Authorize functions and fields as well as objects
Prevent mass assignment, sensitive-field exposure and administrative actions that a valid object lookup alone cannot protect.
Development, Testing · Developers, AppSec engineers
Preserve business invariants under concurrent requests
Make a balance, reservation or approval rule hold when requests overlap, retry and fail halfway through.
Design, Testing · Developers, AppSec engineers
Keep untrusted values out of executable syntax
Choose a safe interface for each interpreter and bound the work performed by parsers and converters.
Development · Developers
Run external programs without command or argument injection
Run programs from an argument list with no shell, end options before user values, and keep untrusted arguments away from Windows batch files.
Development · Developers
Keep untrusted input out of eval, expression languages and templates
Keep code and templates constant, pass input as data, and treat in-process sandboxes as one layer, not a boundary.
Development · Developers
Extract archives without escaping the destination
Prevent traversal, link tricks, overwrites and decompression exhaustion while preserving legitimate file extraction.
Design, Development · Developers, AppSec engineers
Convert untrusted office documents and PDFs in an isolated parser
DOCX, XLSX and ODF files are ZIP archives of XML, and PDFs can carry scripts; the converters that read them are large C and C++ programs with a long CVE history. Check the package before any parser reads it, convert each document in a container with no network, no writable root and hard limits, kill it at a deadline, and re-render to pixels when people will open the result.
Design, Development · Developers, AppSec engineers, Platform engineers and SREs
Secure WebRTC signaling, TURN relays and media servers
WebRTC encrypts media, but signaling decides whose keys you trust and TURN relays wherever it is allowed. Authorize every signaling message, mint short-lived TURN credentials, deny internal addresses and harden media servers.
Design, Development · Developers, Platform engineers and SREs
Review a code change through its trust boundaries
Turn a pull request into a small set of security claims that can be checked against the surrounding system and tests.
Development, Testing · Developers, AppSec engineers
Combine static and dynamic tests around a verified finding
Use analysis tools to find evidence, then retain an application regression that demonstrates the failure and the fix.
Testing, Maintenance · Developers, AppSec engineers
Fuzz a parser and turn crashes into lasting regressions
Build a narrow harness, observe memory and resource failures, minimize the input, and test the repaired parser.
Testing · Developers, AppSec engineers
Preserve framework security controls across the request lifecycle
Trace middleware, persistence and rendering so custom code does not bypass the protections supplied by the framework.
Development · Developers, AppSec engineers
Review mobile storage, links and platform permissions
Keep local artifacts and platform entry points from exposing authority that belongs on the server.
Design, Development · Developers
Constrain desktop IPC and privileged helpers
Keep renderer content, local callers and plugins from turning a narrow feature into unrestricted operating-system access.
Development · Developers, AppSec engineers
Design firmware updates that can recover safely
Connect trusted boot, update authorization, rollback policy and end-of-life behavior to the device’s actual failure modes.
Development, Release · Developers, AppSec engineers
Test smart contracts through state invariants
Define the properties funds and privileges must preserve, then exercise callbacks, transaction sequences and exceptional conditions locally.
Design, Development, Testing · Developers
Parse bounded JSON and XML into an explicit application schema
Separate parser capabilities from schema rules, reject ambiguous and coercible inputs, and implement the boundary in a complete Python project.
Development · Developers, AppSec engineers
Keep untrusted object keys out of prototype and authority paths
Trace an actual nested-merge mutation, replace it with a narrow schema, and make authorization independent of inherited properties.
Development · Developers, AppSec engineers
Harden an Android app's storage, network and entry points
Encrypt local secrets with Android Keystore keys now that Jetpack Security is deprecated, set transport policy in Network Security Configuration, close exported components and mutable PendingIntents, confine WebViews, verify App Links and judge Play Integrity verdicts on the server, mapped to OWASP MASVS 2.1.
Development · Developers, AppSec engineers
Prevent business-logic flaws with server-side invariants
Recompute prices on the server, run workflows as state machines, build reset links from configuration, limit valuable flows, and turn each business rule into an invariant that the database and the tests both check.
Planning, Design, Testing · Developers, AppSec engineers
Case study: Log4Shell (CVE-2021-44228)
How a JNDI lookup in Apache Log4j became internet-wide remote code execution, why transitive and shaded dependencies made it so hard to patch, which mitigations held, and what it teaches about dependency inventory and SBOMs.
Release, Maintenance · Developers, AppSec engineers
Prevent CRLF header injection, log forging and CSV formula injection
Carriage return and line feed separate HTTP header fields, log records and CSV rows, and a leading = turns a spreadsheet cell into a formula. Let the framework write headers, log structured JSON, and neutralize formula triggers in exports.
Development · Developers, AppSec engineers, Platform engineers and SREs
Place each security control in the pipeline and decide what it blocks
Put secrets scanning, SAST, SCA, IaC and image scanning, DAST, fuzzing, attestation and admission control where each sees the right input, block only on findings a developer can act on, and deploy only images the pipeline has attested.
Testing, Release · Developers, AppSec engineers, Platform engineers and SREs
Prevent DOM XSS, postMessage abuse and client-side injection
Trace attacker-controlled values from the URL, messages and storage to the browser APIs that parse HTML or run code, then close those sinks with safe APIs, a sanitizer, Trusted Types and strict message checks.
Development · Developers, AppSec engineers
Harden an iOS app's storage, network and entry points
Store secrets in the Keychain with the narrowest accessibility class, set file protection explicitly, keep App Transport Security on, prefer universal links, constrain WKWebView bridges, keep step-up keys in the Secure Enclave, verify App Attest on the server and ship an accurate privacy manifest, mapped to OWASP MASVS 2.1.
Development · Developers, AppSec engineers
Find, fix and contain memory-safety bugs in C and C++
Recognize out-of-bounds access, use after free, NULL dereference and integer overflow in C and C++, fix them with checked lengths and single ownership, harden release builds, catch the rest with sanitizers and fuzzing, and plan new code in a memory-safe language.
Development, Testing · Developers, Platform engineers and SREs
Prevent NoSQL, LDAP, XPath and expression-language injection
SQL is not the only query language that receives user input. Stop MongoDB operator injection with type checks and $eq, escape LDAP filter values, pass XPath values as variables, and never evaluate SpEL or OGNL built from request data.
Development · Developers, AppSec engineers
Redirect users only to destinations you control
Check every redirect target taken from a request, so attackers cannot borrow your domain for phishing, carry OAuth tokens off-site or steer a server-side fetcher through your redirects.
Design, Development · Developers
Validate input safely and prevent regex denial of service
Find and fix exponential and quadratic regex backtracking with measured examples, choose linear-time engines or timeouts, and build allowlist validation that decodes once and rejects type confusion and parameter pollution.
Development · Developers, AppSec engineers
Audit unsafe Rust, FFI boundaries and crate dependencies
Know what the Rust compiler proves and what it leaves to you: review unsafe code for soundness, wrap foreign calls in small safe functions, decide how overflow and panics behave in release builds, gate crates with RustSec, and replace C one boundary at a time.
Development · Developers, AppSec engineers
Configure HTTP security headers from a tested baseline
Send the response headers that make browsers enforce HTTPS, run only your own scripts, refuse hostile framing and keep cookies on one host, then prove they appear on every kind of response.
Development · Developers
Choose a threat modeling method and turn its findings into tests
Use the four-question frame to scope a design, pick STRIDE, attack trees, LINDDUN or PASTA by the question you need answered, and leave behind threat records and abuse-case tests the team can run.
Design · Developers, AppSec engineers
Case study: MOVEit Transfer mass exploitation (CVE-2023-34362)
How one unauthenticated SQL injection in an internet-facing file transfer product let the Cl0p group steal data from thousands of organizations in days in 2023, how defenders found the web shell, and the vendor and customer controls that would have limited it.
Maintenance, Security program · Developers, AppSec engineers
Write testable security requirements and a security Definition of Done
Derive security requirements from OWASP ASVS 5.0, abuse cases and the threat model, write them as acceptance criteria a test can fail, trace each one to a test or evidence, and close stories against a short security Definition of Done.
Planning, Design, Testing, Security program · Developers, AppSec engineers
Abuse case library: tests and controls by feature
Recurring abuse cases for sign-up and login, password reset, MFA enrolment, invites, file upload, payments and coupons, webhooks, search, export, admin and AI chat or agents: the attacker goal, preconditions, a concrete test and the control, each linked to CWE and CAPEC.
Planning, Design, Testing · Developers, AppSec engineers
Threat pattern library for threat modeling
Thirty-two recurring threat patterns grouped by identity, authorization, parsers, concurrency, integrations, data exposure, supply chain, availability and AI agents, each with where it shows up on a data-flow diagram, mitigations, a verification step and STRIDE, CWE and CAPEC links, plus a YAML catalog and a script that lists patterns per diagram element.
Design · Developers, AppSec engineers
Publish security advisories with CSAF, VEX, CVE records and OSV
What a useful security advisory contains and how to publish it in the formats tools read: a validated CSAF 2.0 VEX document, the CSAF provider files, CVE records through a CNA (CVE Record Format 5.2), and OSV records for open-source packages. Covers the status of CSAF 2.1 as of October 2026.
Maintenance · Developers, AppSec engineers
Prevent file inclusion: LFI, RFI, dynamic imports and template names
Stop request data from choosing which file, module or template your application loads: local and remote file inclusion in PHP, dynamic require() and import() in Node.js, importlib and template names in Python, Thymeleaf view names in Spring, render in Rails, and the allowlist fix that works in all of them.
Development · Developers, AppSec engineers
Create temporary files safely: mkstemp, O_EXCL and private directories
Stop symlink, hardlink and pre-created-file attacks on the temporary files your code writes in shared directories such as /tmp: create each file atomically with O_EXCL and owner-only permissions through mkstemp or its equivalent in shell, Python, Java, Node.js, Go, .NET and Rust, keep related files in a private directory, and treat the Linux protected_* sysctls and systemd PrivateTmp as a backstop.
Design, Development, Testing · Developers
Consume third-party APIs safely (OWASP API10:2023)
Treat every upstream and third-party API response as untrusted input: validate it against a schema, set connect and read timeouts, cap the response size, refuse to follow redirects blindly, keep TLS verification on, and scope the credentials you hold for each provider.
Design, Development · Developers, AppSec engineers
DeFi attack patterns: oracles, flash loans, proxies and signatures
The four smart-contract attack classes beyond reentrancy: price-oracle manipulation, flash-loan amplification, upgradeable-proxy storage collisions and uninitialized implementations, and signature replay, each with vulnerable and fixed Solidity, Foundry tests and verified incidents.
Design, Development, Testing · Developers
Case study: First American's EaglePro document exposure (2019)
How sequential IDs in unauthenticated links exposed First American's title documents in 2019, after its own penetration test found the flaw and a clerical error let it go unfixed.
Development, Testing, Maintenance, Security program · Developers, AppSec engineers, Security leaders
Case study: Citrix Bleed (CVE-2023-4966)
How a NetScaler memory over-read leaked session cookies that bypassed passwords and MFA in 2023, why patching did not end hijacked sessions, and how the pattern returned in 2025.
Maintenance · Developers, AppSec engineers
Case study: Spring4Shell (CVE-2022-22965)
How Spring's data binding let request parameters reach the class loader on JDK 9 and later in 2022, why the denylist workaround leaked, and what it teaches about framework-level mass assignment.
Development, Maintenance · Developers, AppSec engineers, Platform engineers and SREs
Case study: CrowdStrike Channel File 291 (July 2024)
How a CrowdStrike content update crashed Windows hosts in July 2024: a field-count mismatch hidden by wildcard tests, a missing bounds check, and no staged rollout.
Development, Release, Maintenance · Developers, Platform engineers and SREs
Software supply chain
17 guidesProtect the path from pull request to release
Separate untrusted contribution checks from privileged release work and verify the identity of the artifact that is actually deployed.
Development, Release · Developers, Platform engineers and SREs
Generate an SBOM for the software you actually release
Define the inventory boundary, compare build and artifact evidence, and connect the resulting SBOM to an immutable release.
Release · Developers, AppSec engineers, Platform engineers and SREs
Choose SBOM formats and identify components accurately
Separate schema versions, document references and package identities so inventory conversion and advisory matching preserve meaning.
Release · Developers, AppSec engineers
Triage new dependency vulnerability findings
Turn a weekly batch of Dependabot, OSV-Scanner or npm audit findings into a short list of distinct, shipped, reachable issues, each routed to one outcome: fix, not affected, accept or escalate.
Development, Maintenance · Developers, AppSec engineers
Verify artifact signatures against an explicit trust policy
Require the expected artifact, signer and release context before allowing a signed package or image to proceed.
Release · Developers, Platform engineers and SREs
Read SLSA provenance and verify the claim you need
Connect an artifact to its build evidence while distinguishing provenance, build assurance and source controls.
Release · Developers
Keep untrusted CI work outside the release boundary
Review workflow authority, persistent state and artifact handoffs before contributor-controlled code reaches privileged jobs.
Development, Release · Developers
Protect package publication and the update channel
Constrain release identities, verify what consumers receive, and prepare for publisher or update-key compromise.
Release · Developers
Case study: the Shai-Hulud npm worm (2025-2026)
How a self-replicating npm worm turned stolen tokens into hundreds of infected packages in 2025, how its 2026 successors hijacked release pipelines and trusted publishing, what npm and GitHub changed in response, and the publishing, install and response practices that stop it.
Development, Release, Maintenance · Developers, AppSec engineers, Platform engineers and SREs
Case study: the tj-actions/changed-files compromise (CVE-2025-30066)
In March 2025 an attacker moved the version tags of a popular GitHub Action, and of a reviewdog action before it, to code that printed CI secrets into build logs. This case study traces the token chain back to one pull_request_target workflow, sizes the exposure, and shows how it was caught and which controls held.
Development, Release, Maintenance · Developers, AppSec engineers, Platform engineers and SREs
Case study: the xz Utils backdoor (CVE-2024-3094)
How a multi-year maintainer takeover planted a backdoor in xz Utils release tarballs, how build-time injection hid it from the git repository, why a performance anomaly exposed it, which systems shipped it, and what it teaches about reproducible builds and maintainer health.
Development, Release, Maintenance, Security program · Developers, AppSec engineers, Platform engineers and SREs
Case study: event-stream and ua-parser-js, two npm package takeovers
Two ways attackers took over popular npm packages: event-stream (2018), handed to a stranger who added a targeted, encrypted payload through a new dependency, and ua-parser-js (2021), whose maintainer's account was hijacked to publish versions that installed malware for four hours. Timelines, detection and the controls that stop both.
Development, Maintenance, Security program · Developers, Platform engineers and SREs
Stop dependency confusion and typosquatting at install time
Pin every internal package name to its real source, verify installed bytes against a lockfile, and delay or gate install scripts so a public look-alike cannot replace a private dependency.
Development · Developers, AppSec engineers, Platform engineers and SREs
Harden GitHub Actions against workflow and supply-chain attacks
Close the paths that give untrusted pull-request code secrets or a write token: pass context through env, keep pull_request_target away from fork code, pin actions to commit SHAs, scope GITHUB_TOKEN and OIDC, and treat artifacts as data.
Development, Release · Developers, AppSec engineers, Platform engineers and SREs
Protect the source repository: rulesets, reviews and signed commits
Configure the controls every repository that ships software needs: protected branches and tags, required review with CODEOWNERS, signed commits, secret push protection and account security, mapped to the SLSA Source track, the OpenSSF OSPS Baseline and Scorecard.
Development, Testing, Release, Security program · Developers, AppSec engineers, Platform engineers and SREs
Secure the developer workstation: extensions, package managers, secrets and AI agents
Attackers reach the software supply chain through developers' editors, package installs and AI agents. Allow-list extensions, stop install scripts and brand-new versions, keep long-lived secrets off laptops, and lock down repository files that run code when a project opens.
Design, Development, Release · Developers, AppSec engineers, Platform engineers and SREs
Meet the OpenSSF OSPS Baseline as a maintainer: the levels, every Level 1 control on GitHub, and the evidence
Walk through the eight control families and three maturity levels of OSPS Baseline v2026.08.28, meet each Level 1 requirement on a GitHub repository, and keep evidence a consumer can check.
Development, Release, Security program · Developers
Runtime, cloud & APIs
15 guidesReview infrastructure changes as access changes
Inspect the effective permissions, exposure, sensitive state, and recovery implications of a proposed infrastructure change.
Release, Maintenance · Developers, Platform engineers and SREs
Bound API work, not just request counts
Protect availability and operating cost with limits on input, per-request work, concurrency, queues, and downstream spending.
Development, Maintenance · Developers, Platform engineers and SREs
Create security logs someone can investigate
Record meaningful decisions with consistent structure, protect the resulting evidence, and prove that important events reach an operational owner.
Maintenance · Developers, AppSec engineers, Platform engineers and SREs
Run Kubernetes workloads with only the privileges they need
Review pod settings, service accounts and effective permissions together before treating a namespace as an isolation boundary.
Development, Release, Maintenance · Developers, Platform engineers and SREs
Review cloud permissions and role trust together
Distinguish who can obtain a cloud identity from what that identity can do, then test the effective access path.
Release, Maintenance · Developers, Platform engineers and SREs
Test infrastructure policy and detect security-relevant drift
Connect source configuration, the proposed plan and deployed resources so a safe review does not become stale after deployment.
Release, Maintenance · Developers, Platform engineers and SREs
Maintain an API inventory and prevent gateway bypass
Connect documented routes, deployed listeners and backend trust so retired or direct paths do not bypass the intended controls.
Development, Maintenance · Developers, Platform engineers and SREs
Apply security limits to GraphQL, WebSocket and gRPC operations
Carry authorization and resource budgets past the initial HTTP request into resolvers, messages and long-lived streams.
Development, Maintenance · Developers, Platform engineers and SREs
Bound background jobs and make retries safe
Keep queues, workers and paid dependencies within a defined budget when clients retry, cancel or disappear.
Design, Development, Testing, Maintenance · Developers
Keep HTTP request boundaries consistent across intermediaries
Trace framing disagreements, reject ambiguous requests and verify what reaches the origin with a real loopback proxy project.
Maintenance · Developers, Platform engineers and SREs
Prevent shared-cache poisoning and private-response deception
Define lookup and storage policy, trace cache/origin interpretation differences and verify both public reuse and private isolation.
Design, Maintenance · Developers, Platform engineers and SREs
Apply a security baseline across AWS, Azure and Google Cloud
Give workloads platform identities instead of keys, guard the instance metadata endpoint, block public storage, keep audit logs past the default retention, close inbound admin ports and use the native secret store, with tested Terraform for AWS, Azure and Google Cloud.
Release, Maintenance · Developers, AppSec engineers, Platform engineers and SREs
Harden container images from Dockerfile to admission
Build minimal, non-root images pinned by digest, keep secrets out of every layer, then scan, sign and verify the exact digest before it runs with dropped privileges.
Development, Release, Maintenance · Developers, Platform engineers and SREs
Harden the images you ship against CIS, STIG and SCAP benchmarks
Hold each image your team ships (container base images, golden VM images, Kubernetes node images) to a published benchmark through a pinned SCAP Security Guide profile, scan every build with OpenSCAP, and fail the build on any failure that a deviation register does not explain with an owner, an approver and an expiry.
Development, Release, Maintenance, Security program · Developers, AppSec engineers, Platform engineers and SREs
Case study: ingress-nginx CVE-2025-1974 and the exposed admission webhook (2025)
How an admission webhook open to the whole Pod network made ingress-nginx's configuration-injection bugs a 9.8 cluster-takeover risk in 2025, and what its 2026 retirement means.
Development, Maintenance · Developers, Platform engineers and SREs
Identity & cryptography
35 guidesSecrets management: storage, rotation and leaked-secret response
Follow one application credential from issuance through caching, rotation, revocation and restored backups, prove that its old value stops working, and respond correctly when a secret leaks.
Development, Maintenance · Developers, Platform engineers and SREs
ECB mode: why it leaks patterns and what to use instead
Derive exactly what ECB reveals and why a longer key cannot fix it, find where ECB enters real code, and replace it with an authenticated mode.
Design, Development · Developers
Padding oracle attacks
Use a byte-level CBC example to see how a tiny validity signal becomes plaintext information, then design verification that checks more than the error message.
Design, Development · Developers, AppSec engineers
Hash collisions and digital signatures: MD5, SHA-1 and what to use
Distinguish collisions from preimages, follow a colliding pair through signing and verification, and retire MD5 and SHA-1 from the verifiers that still accept them.
Maintenance · Developers
Weak RSA key generation: shared primes, ROCA and safe keys
Recover a toy RSA factor with a greatest common divisor, distinguish shared primes, structured primes, duplicate keys and key length, and check a fleet of real public keys.
Maintenance · Developers
RC4 keystream bias
Understand why fresh RC4 keys do not remove keystream bias and how repeated secret positions turn a small statistical effect into evidence.
Design, Development · Developers
64-bit block ciphers and the Sweet32 mechanism
Calculate the birthday effect for 64-bit blocks and derive the CBC relation that can turn a collision into a plaintext disclosure.
Design, Development · Developers
WEP: RC4 key reuse and weak IVs
Separate WEP’s repeated-keystream failure, weak-IV key recovery, and unkeyed integrity weakness through a concrete two-packet exercise.
Design, Development · Developers
Flame: MD5 certificate forgery
Follow how a weak digest and an overpowered certificate trust path enabled forged code-signing authority, without equating the event with RSA key theft.
Design, Release, Maintenance · Developers
Lucky Thirteen and POODLE: two different oracles
Compare two CBC oracles by their signal, protocol rules, and attacker prerequisites instead of treating them as interchangeable padding bugs.
Design, Development · Developers
FREAK and Logjam: export-grade key exchange
Trace two export-grade downgrade paths and separate RSA factorization from finite-field Diffie–Hellman discrete logarithms.
Design, Maintenance · Developers
DROWN: one RSA key across incompatible protocols
Map an RSA key across services to see how an SSLv2 oracle could compromise TLS traffic on a different endpoint.
Design, Development · Developers
ROCA: structured RSA key generation
Understand why mathematically structured RSA primes were factorable despite normal key lengths, then plan replacement around generation provenance.
Design, Maintenance · Developers
Session management: cookies, timeouts, rotation and revocation
Model authentication as transitions in server authority, set session cookies and timeouts to current NIST and OWASP values, and verify fixation prevention, expiry, reauthentication, revocation and stolen-cookie defenses.
Development · Developers
Password storage: hashing parameters and rehash on login
Choose Argon2id, scrypt, PBKDF2 or bcrypt with current minimum parameters, store a versioned hash, and upgrade old hashes after a successful login without overwriting a reset.
Development · Developers
OAuth 2.0 and OpenID Connect login: authorization code with PKCE
Implement OAuth 2.0 and OpenID Connect login with the authorization code flow and PKCE, keep each transaction bound to its browser, and block redirect, mix-up, code-injection and token-theft attacks.
Development · Developers
JWT validation: algorithms, keys, claims and key rollover
Validate a JWT against a fixed algorithm, trusted keys and the expected issuer, audience and type, reject the known header attacks, and rotate signing keys without accepting arbitrary keys or breaking valid tokens.
Development · Developers
Passkeys and MFA: WebAuthn enrollment, sign-in and replacement
Register, verify and replace passkeys with WebAuthn so phishing resistance survives the account’s whole lifecycle, and map passkeys and other MFA methods to the NIST SP 800-63B-4 assurance levels.
Development · Developers
Account recovery: password resets, help-desk resets and account linking
Treat password resets, support-desk recovery and account linking as new grants of authority: single-use high-entropy proofs, atomic consumption, session revocation, and stable identity rather than email matching.
Development · Developers, AppSec engineers
AEAD records: AES-GCM nonces, associated data and key limits
Build an encrypted record whose tag binds ciphertext to the intended tenant, record, purpose and format, keep nonces unique within each key’s usage limit, and verify the design with actual AES-GCM.
Design, Development · Developers
Envelope encryption and key rotation: data keys, KMS keys and backups
Encrypt each record with its own data key, wrap that key in a KMS or HSM key, and keep wrapping-key rotation, data re-encryption, key deletion and restored backups as separate, tested operations.
Design, Maintenance · Developers, Platform engineers and SREs
Operate TLS and certificates: configuration, renewal and verification
Configure a modern TLS profile with hybrid post-quantum key exchange, automate renewal for certificate lifetimes that fall to 47 days, and verify every termination point with a fresh handshake.
Design, Maintenance · Developers, Platform engineers and SREs
Authorization models: RBAC, ABAC, ReBAC and policy as code you can test
Translate roles, attributes and relationships into explicit subject-action-resource decisions, prevent broken object level authorization (BOLA), and verify ownership and tenant boundaries with tests.
Design, Development · Developers
Data minimization and retention: collect less and prove that deletion works
Design collection and deletion around a data-flow graph that includes logs, derived tables, exports and restored backups, and use per-person keys so deletion can reach copies you cannot edit.
Planning, Design, Security program · Developers, AppSec engineers
Tokenization, pseudonymization and privacy transformations: choose deliberately
Choose between vault tokens, keyed pseudonyms, format-preserving encryption, aggregation and differential privacy by the joins, reversibility and leakage each allows, and test re-identification on the data you release.
Planning, Design, Security program · Developers
SAML single sign-on: verify signed assertions without losing the identity boundary
Bind a validated SAML assertion to its trusted issuer, the exact signed element, your service, the browser request and a replay record before creating a local session, and keep your SAML library ahead of its advisories.
Development · Developers
SCIM deprovisioning: make account disablement remove every usable authority
Connect SCIM resource updates to current sessions, tokens, group-derived permissions and background jobs, with explicit tenant mapping, CAEP revocation events and a measurable revocation contract.
Development · Developers
Choose cryptographic algorithms and parameters by job
A sourced quick reference for October 2026: which algorithm and parameters to use for encryption, hashing, passwords, MACs, signatures, key agreement, key derivation, randomness and TLS, the matching APIs in Node.js, Python, Java, Go and .NET, and where post-quantum migration stands.
Design, Development · Developers
Defend JWTs against forgery, confusion and replay
Verify a JWT as an issuer-, type- and audience-bound assertion with an algorithm allowlist and trusted keys, closing the alg "none", key-confusion, header-injection, weak-secret and replay attacks.
Development · Developers
Contain a leaked secret, then investigate and clean up
Revoke an exposed API key, token or private key at its issuer before anything else, end the sessions it minted, check the provider's logs, then remove every copy and replace it with a credential that expires on its own.
Development, Maintenance · Developers, AppSec engineers, Platform engineers and SREs
Stop account takeover with the right MFA and login defenses
Rank MFA options by the attacks they stop, implement TOTP and push approvals correctly, and close the login, reset and recovery paths that attackers use instead of breaking the second factor.
Development · Developers, AppSec engineers
Secrets at runtime: Vault, Kubernetes Secrets, CSI driver, External Secrets and SOPS
How a running workload should get its credentials: encrypt Kubernetes Secrets with a KMS v2 provider and lock down RBAC, mount from an external store with the Secrets Store CSI Driver, sync with External Secrets Operator, issue dynamic credentials with Vault and its Agent Injector, keep Git copies encrypted with SOPS, and make rotation reach the process.
Design, Development, Maintenance · Developers, Platform engineers and SREs
Case study: the Okta support-system breach and session tokens in HAR files (2023)
How a service account password saved to a personal browser profile let an attacker download customers' HAR files from Okta's support system, replay the session tokens inside them against five customers, and stay unseen for two weeks; and why HAR files are credentials, admin sessions need binding, and every exposed credential must be rotated.
Development, Maintenance · Developers, Platform engineers and SREs
Case study: certificate expiry outages at Ericsson (2018) and Microsoft Teams (2020), and Equifax's blind spot
How an expired certificate inside Ericsson's core-network software cut mobile data for millions in about 11 countries, how an expired authentication certificate took Microsoft Teams offline, how an expired inspection certificate left Equifax blind for 19 months, through its 2017 breach, and the inventory, automation and testing that prevent each.
Maintenance · Developers, AppSec engineers, Platform engineers and SREs
Case study: Storm-0558 and the forged Microsoft tokens (2023)
How a stolen 2016 consumer signing key and a token validation gap let Storm-0558 read enterprise Exchange Online mail in 2023, and what the review board found about rotation, logging and culture.
Development, Maintenance, Security program · Developers, Platform engineers and SREs
Governance & frameworks
2 guidesRun a developer security training program that changes code
Build role-based, hands-on developer security training from this site's learning paths, labs and fix cards, meet PCI DSS 6.2.2, NIST SSDF PO.2.2 and ISO/IEC 27001 A.6.3 with real evidence, and measure the effect with repeat findings instead of completion rates.
Security program · Developers, AppSec engineers, Security leaders
Build an application security career: roles, skills, portfolio and certifications
The main application security role tracks (AppSec engineer, product security engineer, security champion, platform security engineer, security architect), the skills expected at each level, how to build a portfolio a hiring team can verify using this site's labs, projects and fix cards, and what common certifications do and do not show.
Security program · Developers, AppSec engineers, Security leaders
AI security
19 guidesContain prompt injection at the application boundary
Assume retrieved content can influence model output; enforce data access and consequential actions in components the model cannot authorize for itself.
Design, Development · Developers, AppSec engineers, Platform engineers and SREs
Keep retrieval inside the user’s data boundary
Carry document permissions through ingestion, retrieval, caching and citations so a model never receives another tenant’s records.
Design, Development · Developers, AppSec engineers, Platform engineers and SREs
Authorize agent tools outside the model
Bind each proposed action to the user, resource and approved arguments before allowing a tool to cause a side effect.
Design, Development · Developers, AppSec engineers, Platform engineers and SREs
Keep generated output out of executable contexts
Choose safe rendering and narrow operations so model text cannot become browser code, database syntax or an unrestricted command.
Design, Development · Developers, AppSec engineers, Platform engineers and SREs
Build evaluations around prohibited outcomes
Test the application’s actual security boundaries, preserve legitimate tasks and distinguish deterministic enforcement from variable model behavior.
Design, Testing, Security program · Developers, AppSec engineers, Platform engineers and SREs
Red-team LLM applications and agents by their effects
A red-teaming method for LLM features and agents: scope the whole system, map attacks to OWASP and MITRE ATLAS identifiers, score trials from observed effects, report rates with confidence intervals and retest on every model or provider change.
Design, Testing, Security program · Developers, AppSec engineers, Platform engineers and SREs
Bound agent spending, memory and recovery
Enforce budgets and stop conditions outside the model, and make retained context and side effects recoverable.
Design, Development · Developers, AppSec engineers, Platform engineers and SREs
Treat model releases as executable supply-chain inputs
Verify provenance, constrain loading and preserve the relationship between model weights, configuration and runtime dependencies.
Development, Release · Developers, AppSec engineers, Platform engineers and SREs
Protect training and retrieval data from targeted poisoning
Track who can influence datasets, keep evaluation independent and investigate targeted behavior changes without relying on aggregate accuracy.
Development, Testing, Release, Security program · Developers, AppSec engineers, Platform engineers and SREs
Constrain MCP and multi-agent trust boundaries
Validate each connection and delegated action without treating a token for another service, a tool description, another agent or a state handle as authority.
Design, Development · Developers
Turn NIST AI RMF, ISO/IEC 42001 and EU AI Act duties into engineering evidence
What the NIST AI RMF and its Generative AI Profile, ISO/IEC 42001 and the EU AI Act, as amended in 2026, ask of teams that build AI features, turned into engineering practices and one set of evidence. Not legal advice.
Planning, Testing, Security program · Developers, AppSec engineers, Platform engineers and SREs, Security leaders
Secure AI-assisted development with coding assistants and agents
Treat generated code, suggested packages, repository text and MCP servers as untrusted inputs, and confine coding agents with OS-level isolation and short-lived, narrowly scoped credentials.
Design, Development · Developers, AppSec engineers
Call a hosted LLM API safely
A code-first checklist for wiring up an OpenAI or Anthropic API call from a backend: keep keys server-side, redact PII before prompts and logs, choose provider retention settings deliberately, validate structured output and still treat it as untrusted, and set timeouts, retries and per-user cost caps.
Design, Development · Developers, AppSec engineers
Sandbox model-generated code and computer-use agents
Run the code an agent writes, and agents that drive a browser or desktop, inside a boundary built for hostile code: a disposable runtime with no secrets and no default network, hard resource limits, and a person in front of every side effect.
Design, Development · Developers, Platform engineers and SREs
Keep secrets and controls out of hidden context (OWASP LLM08:2026)
OWASP LLM08:2026 Hidden Context Exposure, which replaced System Prompt Leakage: why system prompts, tool schemas and retrieved policy text get extracted, what must never be in them, and how to enforce rules where a leak changes nothing.
Design, Development · Developers, AppSec engineers
Defend agent memory and context against poisoning (OWASP ASI06)
OWASP ASI06 Memory & Context Poisoning: how an instruction or false fact saved once in agent memory, conversation summaries or a retrieval store steers later sessions, users and agents, and the write, scope, provenance, expiry and recovery controls that contain it.
Design, Development · Developers, AppSec engineers
Case study: Moffatt v. Air Canada, a chatbot that misstated the refund policy (2022-2024)
How an airline's website chatbot told a grieving customer they could claim a bereavement fare after travel, what the British Columbia Civil Resolution Tribunal decided in February 2024, and the grounding, testing and correction practices that keep an automated answer consistent with the policy it describes.
Design, Development, Maintenance · Developers
Case study: the Nx s1ngularity compromise and its AI-assisted payload (2025)
How a pull-request-title injection in a GitHub Actions workflow on an outdated branch gave an attacker the Nx npm token in August 2025, how the malicious versions tried to turn developers' own AI command-line tools into file-search agents, and the workflow, publishing and agent controls that stop the same chain.
Design, Development, Release, Maintenance · Developers, Platform engineers and SREs
Case study: the Amazon Q Developer extension compromise (2025)
How an over-scoped GitHub token, extracted from an AWS CodeBuild pull request build, let a threat actor commit code to the Amazon Q Developer extension for VS Code that shipped in version 1.84.0 in July 2025, why the injected code aimed at the Q Developer CLI failed, and the CI and AI-agent controls the incident argues for.
Design, Development, Testing, Release, Maintenance · Developers, Platform engineers and SREs