Copier safe template has filesystem write access outside destination path
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 9.9.1
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: poc
- Automatable: no
- Technical impact: partial
Summary
Copier library and CLI app for rendering project templates. From 7.1.0 to before 9.9.1, Copier suggests that it's safe to generate a project from a safe template, i.e. one that doesn't use unsafe features like custom Jinja extensions which would require passing the --UNSAFE,--trust flag. As it turns out, a safe template can currently write files outside the destination path where a project shall be generated or updated. This is possible when rendering a generated directory structure whose rendered path is either a relative parent path or an absolute path. Constructing such paths is possible using Copier's builtin pathjoin Jinja filter and its builtin _copier_conf.sep variable, which is the platform-native path separator. This way, a malicious template author can create a template that overwrites arbitrary files (according to the user's write permissions), e.g., to cause havoc. This vulnerability is fixed in 9.9.1.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: poc · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- copier-org copier
From 7.1.0 · fixed in 9.9.1
- copierPyPI
From 7.1.0 · fixed in 9.9.1