vulnerability / NVI-00018611 / Revision 1
tar has a PAX header desynchronization issue
GitHub lists this reviewed advisory for tar. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
tar
source listed<= 0.4.45
### Summary When a tar stream contains multiple "header" entries prior to a file entry, tar-rs applies the PAX header (`x`) to the _next_ entry in the stream, regardless of type. For example, a stream of `x -> L -> file` (PAX, GNU longname, file) would result in `x`'s extensions being applied to `L` rather than to `file`. Per POSIX pax, this is incorrect: a PAX header always applies to a file entry, not any intermediary entries. See the "pax Header Block" section for the specific prescription there. As a result of this, an attacker can contrive a tar containing a sequence of tar headers such that tar-rs applies the PAX header's `size` extension to the next header in sequence, effectively desynchronizing the stream and enabling tar-rs specific skippage/extraction of members. In other words, a file can be contrived to extract differently on tar-rs than on other tar parsers. ### PoC This tar (zipped for size) demonstrates the desynchronization: with `tar tvf`: ``` % tar tvf tests/archives/pax-overrides-extension-heade
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database
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04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
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- GHSA-3pv8-6f4r-ffg2 ↗
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Public revision history
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- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.