basic-ftp is an FTP client for Node.js. Prior to 6.2.1, Client.list() can be forced by a malicious or compromised FTP server to spend quadratic CPU time parsing a directory listing because the RE_LINE expression in src/parseListUnix.ts backtracks across adjacent variable-length owner and group fields when a long Unix-style line has a valid prefix but cannot satisfy the later size and date fields. parseList() selects a parser from the last nonblank line and then applies it to every line, so a normal final line can select the Unix parser while an earlier crafted line blocks the Node.js event loop and freezes the process. This issue is fixed in version 6.2.1.
Weakness
The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.
Potential Mitigations
Related Attack Patterns
References
- https://github.com/patrickjuchli/basic-ftp/commit/d0d9e07c56e519587bb50532ac6eadbb0cb0cfe9
- https://github.com/patrickjuchli/basic-ftp/releases/tag/v6.2.1
- https://github.com/patrickjuchli/basic-ftp/security/advisories/GHSA-c475-qrg2-pj4r
- https://github.com/patrickjuchli/basic-ftp/security/advisories/GHSA-c475-qrg2-pj4r