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.
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.
By setting up appropriate symlinks, a malicious user could cause arbitrary files to be overwritten with debugging information.
Pending patch information by the vendor, CERT/CC is unaware of a practical solution to this problem.
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Notified: May 25, 2001 Updated: June 08, 2001
We have not received a statement from the vendor.
The vendor has not provided us with any further information regarding this vulnerability.
The CERT/CC has no additional comments at this time.
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Group | Score | Vector
Base | |
Temporal | |
Environmental | |
The original report of this vulnerabilty was by Jakub Vlasek .
This document was last modifed by Tim Shimeall.
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