CVE-2018-1000888
HIGHArchive_Tar contains Potential RCE if filename starts with phar://
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
pear/archive_tarReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
PEAR Archive_Tar version 1.4.3 and earlier contains a CWE-502, CWE-915 vulnerability in the Archive_Tar class. There are several file operations with $v_header['filename'] as parameter (such as file_exists, is_file, is_dir, etc). When extract is called without a specific prefix path, we can trigger unserialization by crafting a tar file with phar://[path_to_malicious_phar_file] as path. Object injection can be used to trigger destruct in the loaded PHP classes, e.g. the Archive_Tar class itself. With Archive_Tar object injection, arbitrary file deletion can occur because @unlink($this->_temp_tarname) is called. If another class with useful gadget is loaded, it may possible to cause remote code execution that can result in files being deleted or possibly modified. This vulnerability appears to have been fixed in 1.4.4.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | pear/archive_tar | all versions | 1.4.4 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
PEAR Archive_Tar < 1.4.4 - PHP Object Injection
by Fariskhi Vidyan · Jan 10, 2019
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pear/archive_tar. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update pear/archive_tar to 1.4.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-1000888 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2018-1000888 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2018-1000888. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2018-1000888 in your dependencies?
O3 detects CVE-2018-1000888 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.