A tar archive is a container file that bundles multiple files and directories into a single package while preserving structure, permissions, and attributes. It is widely used for backups, software distribution, and transfers because it keeps related content together and makes later extraction predictable.
What a tar archive is for
A tar archive is primarily a packaging format, not a compression format. It groups many files into one portable container so that directory structure, file names, permissions, and other metadata travel together. That makes it useful when the goal is to preserve a filesystem snapshot or move a software tree without flattening its layout.
Because tar was designed for bundling, the archive can contain mixed content, nested paths, and empty directories in a way that a simple file copy cannot always represent cleanly. In practice, that predictability is one reason tar remains common in Unix and Linux workflows.
How tar preserves structure and metadata
The value of tar is that it records the relationship between items, not just their bytes. When extracted, the original tree can be recreated with the same relative paths, which matters for backups, source distributions, and application delivery packages that expect a particular layout.
Tar archives may also preserve ownership, permissions, timestamps, symbolic links, and similar attributes depending on how they are created and extracted. That means the archive is often treated as a fidelity-preserving transport layer for files, rather than a security control in its own right.
Common use cases and operational context
Tar is widely used for backups, release bundles, container image layers, and transfer packages because it keeps related files together in a form that is easy to store and distribute. Compression is often added separately, which is why people commonly encounter tar.gz or tar.xz rather than tar alone.
Operationally, tar is most useful when the recipient needs the archive to unpack into a known structure. That makes it well suited to packaging software source trees, preserving configuration bundles, and moving data sets between systems that share Unix-like conventions.
Extraction behavior and trust boundaries
Extraction is where a tar archive becomes security-relevant. The archive can request paths, ownership, or file modes that are unexpected if it comes from an untrusted source, so the act of unpacking should be treated as a trust-boundary event, not a routine file open.
For that reason, archive handling should be careful about where files are extracted and whether the contents match expectations before they are executed or deployed. A tar file is only a container, but its contents may still be used to deliver malicious scripts, overwrite local files, or hide unsafe paths if extraction is careless.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
NIST SP 800-53 Rev 5, CIS Controls v8, OWASP ASVS and SLSA set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST SP 800-53 Rev 5 | CM-8 — System Component Inventory | Tar archives depend on knowing what files are packaged and extracted. |
| SI-7 — Software, Firmware, and Information Integrity | Archive contents should be validated before use or deployment. | |
| Recommendation — Maintain a current inventory of archived assets so packaged files can be traced and validated before extraction. Verify archive integrity and inspect extracted contents before trusting them in production. | ||
| CIS Controls v8 | CIS-3 — Data Protection | Tar archives often transport sensitive data that needs protection at rest and in transit. |
| CIS-16 — Application Software Security | Archive extraction often feeds software deployment and update workflows. | |
| Recommendation — Classify and protect archived data according to its sensitivity before distribution or storage. Treat archive unpacking as part of the software delivery chain and validate artifacts before release. | ||
| OWASP ASVS | V5 — File Handling | Tar archives are a file packaging and extraction mechanism with path-handling implications. |
| Recommendation — Validate archive paths and extracted filenames to prevent unsafe file handling during unpacking. | ||
| SLSA | Supply-chain Levels for Software Artifacts | Tar archives commonly package software artifacts that need provenance and integrity checks. |
| Recommendation — Use provenance and integrity verification for archived build artifacts before release or deployment. | ||
Related resources from NHI Mgmt Group
- How do you patch or mitigate CVE-2020-36193 (PEAR Archive_Tar Improper Link Resolution)?
- How do you patch or mitigate CVE-2020-28949 (PEAR Archive_Tar Deserialization of Untrusted Data)?
- Is CVE-2020-36193 (PEAR Archive_Tar Improper Link Resolution) being exploited in the wild?
- Is CVE-2020-28949 (PEAR Archive_Tar Deserialization of Untrusted Data) being exploited in the wild?
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Reviewed and updated by the NHIMG editorial team on October 30, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org