Title: IBM AIX Runtime Linker Search Path Vulnerability
Severity: MODERATE
Description:
An issue has been reported in the runtime linker for IBM AIX operating systems. The runtime linker determines program dependencies when dynamic executables are loaded. Programs compiled with non-native compilers may still use the AIX runtime linker to link dynamic libraries when a program is executed.
The IBM AIX runtime linker is reported to use an insecure search path for dynamic libraries for programs that are compiled with a non-AIX compiler, such as GCC. The source of this issue is that the current working directory or possibly a user-specified path will be searched before other system directories. This can occur with programs that do not explicitly set a library search path at compile time.
An attacker could take advantage of this condition by placing a malicious library in the current working directory. This could allow for privilege escalation with programs that are setuid/setgid.
This issue is well documented in the AIX man pages. It is a deviation from the behavior of other Unix linkers, and as such may be confusing to those who are not familiar with the AIX specific behavior.
Portable OpenSSH compiled with GCC was reported as an example of a program that may introduce this issue, though the problem itself is due to the behavior of the runtime linker. This issue was also reported with Sendmail 8.10, compiled with a non-native compiler.
BID 7468 described the same issue and is being retired as a result. This BID is being updated with additional details from that entry.
Affected Products:
- IBM AIX 4.1.0
- IBM AIX 4.1.1
- IBM AIX 4.1.2
- IBM AIX 4.1.3
- IBM AIX 4.1.4
- IBM AIX 4.1.5
- IBM AIX 4.2.0
- IBM AIX 4.2.1
- IBM AIX 4.3.0
- IBM AIX 4.3.1
- IBM AIX 4.3.2
- IBM AIX 4.3.3
- IBM AIX 5.1.0
- IBM AIX 5.1.0 L
- IBM AIX 5.2
References:
- Darren Tucker: Darren Tucker's OpenSSH Page
- IBM: AIX Fix Distribution Service
- IBM: IBM Support Databases
- IBM: Portable OpenSSH: Dangerous AIX linker Behavior - NOT!
- OpenSSH: OpenSSH Project Homepage
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