Allele Security Alert
Delete directory using symlink when decompressing tar
RubyGems 2.7.6 and later through 3.0.2
Proof of concept
A directory traversal issue was discovered in RubyGems 2.7.6 and later through 3.0.2. Before making new directories or touching files (which now include path-checking code for symlinks), it would delete the target destination. If that destination was hidden behind a symlink, a malicious gem could delete arbitrary files on the user’s machine, presuming the attacker could guess at paths. Given how frequently
gem is run as sudo, and how predictable paths are on modern systems (
/usr, etc.), this could likely lead to data loss or an unusable system.
March 2019 Security Advisories
Validate that symlinks cannot cause dirs outside of the gem to be deleted
If there is any error in this alert or you wish a comprehensive analysis, let us know.
Last modified: June 19, 2019