sbt: Source dependency feature (via crafted VCS URL) leads to arbitrary code execution on Windows

Summary

On Windows, sbt uses Process("cmd", "/c", ...) to run VCS commands (git, hg, svn). The URI fragment (branch, tag, revision) is user-controlled via the build definition and passed to these commands without validation. Because cmd /c interprets &, |, and ; as command separators, a malicious fragment can execute arbitrary commands.

Patched version

Technically, sbt 1.12.7 is patched, but it has a bug that makes source dependency non-functional, so update to sbt 1.12.8 or later instead.

Details

• Resolvers.scala L84–95 — git resolver passes uri.getFragment() to run() without sanitization
• Resolvers.scala L137–145 — run() uses Process("cmd", "/c", ...) on Windows, so cmd interprets && as command separator

PoC

# build.properties
# sbt.version=1.12.5  # Tested on those two versions of sbt
sbt.version=2.0.0-RC9

// build.sbt

ThisBuild / scalaVersion := "2.12.19"

lazy val root = project
  .in(file("."))
  .dependsOn(vulnerable)

lazy val vulnerable = RootProject(
  uri("https://github.com/sbt/io.git#develop%26%26calc.exe")
)

Impact

Windows users are impacted. An attacker can execute arbitrary Windows commands if they control the dependency URI.