CVE-2006-1542 in Python
Summary
by MITRE
Stack-based buffer overflow in Python 2.4.2 and earlier, running on Linux 2.6.12.5 under gcc 4.0.3 with libc 2.3.5, allows local users to cause a "stack overflow," and possibly gain privileges, by running a script from a current working directory that has a long name, related to the realpath function. NOTE: this might not be a vulnerability. However, the fact that it appears in a programming language interpreter could mean that some applications are affected, although attack scenarios might be limited because the attacker might already need to cross privilege boundaries to cause an exploitable program to be placed in a directory with a long name; or, depending on the method that Python uses to determine the current working directory, setuid applications might be affected.
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Analysis
by VulDB Data Team • 06/18/2024
The vulnerability described in CVE-2006-1542 represents a stack-based buffer overflow affecting Python interpreter versions 2.4.2 and earlier when executing on specific Linux kernel and compiler combinations. This flaw manifests when a Python script is executed from a working directory with an excessively long name, specifically triggering issues within the realpath function implementation. The vulnerability operates through the exploitation of stack memory boundaries, where the interpreter fails to properly validate the length of directory paths during execution. The affected environment configuration includes Linux kernel 2.6.12.5, gcc 4.0.3 compiler, and libc 2.3.5 library, creating a specific attack surface that leverages the interaction between these components.
The technical mechanism behind this vulnerability involves the Python interpreter's handling of current working directory paths through the realpath system call, which can overflow the stack buffer when processing directory names exceeding predetermined limits. The stack-based nature of the overflow means that memory corruption occurs in the program's stack space, potentially allowing attackers to overwrite return addresses and execute arbitrary code. This type of vulnerability falls under CWE-121, which specifically addresses stack-based buffer overflow conditions, and aligns with ATT&CK technique T1059.006 for interpreter-based execution. The vulnerability's exploitation requires local access and specific environmental conditions, making it less immediately dangerous than remote exploits but still potentially severe given the privilege escalation implications.
The operational impact of this vulnerability extends beyond simple denial of service, as it could potentially enable privilege escalation under certain circumstances. While the initial attack vector requires local execution and the ability to place malicious scripts in directories with long names, the vulnerability's potential for exploitation increases when considering applications that run with elevated privileges. Setuid applications executing Python scripts could be particularly vulnerable, as the interpreter might inherit elevated privileges during execution. The attack scenario becomes more complex when considering that attackers would typically need to establish a foothold in the system to place malicious code in directories with long names, though this limitation does not eliminate the risk entirely. The vulnerability's classification as potentially exploitable rather than definitively vulnerable reflects the complexity of real-world exploitation scenarios and the specific environmental requirements needed for successful exploitation.
Mitigation strategies for CVE-2006-1542 focus primarily on upgrading to patched Python versions where the buffer overflow has been addressed through proper input validation and stack boundary checking. System administrators should prioritize updating Python installations to versions 2.4.3 or later, which contain fixes for the realpath function handling. Additionally, implementing strict path length restrictions and monitoring for unusually long directory names in critical execution paths can provide defense-in-depth measures. Security hardening practices should include disabling unnecessary setuid applications and ensuring proper privilege separation within the operating system. The vulnerability serves as a reminder of the importance of proper buffer management in interpreter implementations and highlights the need for thorough security testing of core system components. Organizations should also consider implementing automated vulnerability scanning tools to identify potentially affected systems and ensure timely patch deployment across their infrastructure.