Overview
Some versions of ld.so, the loader for shared libraries in UNIX/LINUX, do not properly clear risky environment variables, allowing a symlink attack to overwrite arbitrary files.
Description
LD_DEBUG_OUTPUT specifies a directory in which ld.so creates a file with a predictable name based on the process ID. ld.so uses this file to store debugging information. The current version of ld.so does not unset the environment variable LD_DEBUG_OUTPUT prior to calling setuid root programs. Even though setuid root programs are forced to ignore the LD_DEBUG_OUTPUT variable, output would be generated there by programs called from setuid root programs. |
Impact
By setting up appropriate symlinks, a malicious user could cause arbitrary files to be overwritten with debugging information. |
Solution
Pending patch information by the vendor, CERT/CC is unaware of a practical solution to this problem. |
Vendor Information
CVSS Metrics
| Group | Score | Vector |
|---|---|---|
| Base | ||
| Temporal | ||
| Environmental |
References
Acknowledgements
The original report of this vulnerabilty was by Jakub Vlasek .
This document was last modifed by Tim Shimeall.
Other Information
| CVE IDs: | CVE-2000-0959 |
| Severity Metric: | 0.11 |
| Date Public: | 2000-09-26 |
| Date First Published: | 2001-07-24 |
| Date Last Updated: | 2001-07-31 16:29 UTC |
| Document Revision: | 8 |