RUSTSEC-2021-0071

grep-cli may run arbitrary executables on Windows

Issued
Package
grep-cli (crates.io)
Type
Vulnerability
Categories
  • code-execution
Aliases
Details
https://github.com/BurntSushi/ripgrep/issues/1773
Patched
  • >=0.1.6
Keywords
  • windows
  • ripgrep
  • PATH
  • arbitrary
  • binary
Affected OSes
  • windows
Affected Functions
Version
grep_cli::DecompressionReader::new
  • <0.1.6

Description

On Windows in versions of grep-cli prior to 0.1.6, it's possible for some of the routines to execute arbitrary executables. In particular, a quirk of the Windows process execution API is that it will automatically consider the current directory before other directories when resolving relative binary names. Therefore, if you use grep-cli to read decompressed files in an untrusted directory with that directory as the CWD, a malicious actor to could put, e.g., a gz.exe binary in that directory and grep-cli will use the malicious actor's version of gz.exe instead of the system's.

This is also technically possible on Unix as well, but only if the PATH variable contains .. Conventionally, they do not.

A DecompressionReader has been fixed to automatically resolve binary names using PATH, instead of relying on the Windows API to do it.

If you use grep-cli's CommandReader with a std::process::Command value on Windows, then it is recommended to either construct the Command with an absolute binary name, or use grep-cli's new resolve_binary helper function.

To be clear, grep-cli 0.1.6 mitigates this issue in two ways:

While the first mitigation fixes this issue for sensible values of PATH when doing decompression search, the second mitigation is imperfect. The more fundamental issue is that std::process::Command is itself vulnerable to this.

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