Fix CRLF and log injection in Java and Spring Boot
==================================================

Encode request values before they reach a log line, turning every control
character into a visible escape, or use Spring Boot's structured JSON logging;
never delete only LF. For download names, keep only letters, digits and a few
separators, then build the header with
ContentDisposition.attachment().filename(name, UTF_8) instead of concatenating
it.

Page: https://softwaresecurity.com/fix/crlf-log-injection/java-spring/

What is in this archive
-----------------------
crlf-log-injection/java-spring/   the project: three implementations of the same code and one test suite
  src/main/java/com/example/audit/impl/VulnerableRequestDataOutput.java   (vulnerable)
  src/main/java/com/example/audit/impl/FixedRequestDataOutput.java   (fixed)
  src/main/java/com/example/audit/impl/WrongRequestDataOutput.java   (a plausible fix that still fails)
run-all.mjs   runs the tests in all three modes and checks the results (Node.js only)
LICENSE-CODE.txt

Run it
------
  Tested with OpenJDK 21.0.12.1 (Homebrew), Maven 3.9.16. run-all.mjs needs
  Node.js 22 or later. Supported versions:
  https://softwaresecurity.com/fix/versions/

  From the crlf-log-injection/java-spring folder, install the dependencies once
  (this needs network access):

    mvn -B -q test

  Then run the tests. IMPL chooses the implementation the tests load:

    # every test passes
    IMPL=fixed mvn -B -o -q test
    # an exploit test fails
    IMPL=vulnerable mvn -B -o -q test
    # a test fails
    IMPL=wrong mvn -B -o -q test

  The JUnit report is written to target/surefire-reports/TEST-*.xml. To run all
  three modes and check the results in one step, run the harness from this top
  folder (it needs only Node.js; --install runs the install step first):

    node run-all.mjs --install crlf-log-injection/java-spring
    node run-all.mjs crlf-log-injection/java-spring

Verified
--------
  11 October 2026 on macOS 27.0 (Darwin 27.0.0, arm64), with java OpenJDK
  21.0.12.1, maven 3.9.16, springBoot 4.1.1, tomcat 11.0.26, semgrep 1.180.0.
  Versions and results hold for that date: run the tests with your own versions
  before relying on the fix.

Licence
-------
  The code is MIT licensed (LICENSE-CODE.txt). The page text is CC BY 4.0.
