CVE-2008-3142 in Python
Summary
by MITRE
Multiple buffer overflows in Python 2.5.2 and earlier on 32bit platforms allow context-dependent attackers to cause a denial of service (crash) or have unspecified other impact via a long string that leads to incorrect memory allocation during Unicode string processing, related to the unicode_resize function and the PyMem_RESIZE macro.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 08/15/2019
The vulnerability identified as CVE-2008-3142 represents a critical buffer overflow condition affecting Python 2.5.2 and earlier versions when operating on 32-bit platforms. This flaw manifests during Unicode string processing operations, specifically when the unicode_resize function encounters excessively long strings that trigger incorrect memory allocation behavior. The issue stems from improper handling of memory reallocation during Unicode string manipulation, creating conditions where attacker-controlled input can cause memory corruption. The vulnerability operates within the Python interpreter's memory management subsystem, specifically targeting the PyMem_RESIZE macro which is responsible for adjusting memory allocations for Python objects. This type of vulnerability falls under CWE-122, which categorizes improper restriction of operations within a memory buffer, and represents a classic example of heap-based buffer overflow that can be exploited to cause system instability.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable more sophisticated attacks depending on the execution environment. When a maliciously crafted long string is processed through Python's Unicode handling mechanisms, the incorrect memory allocation causes the application to crash or behave unpredictably. The vulnerability is context-dependent, meaning that exploitation requires specific conditions where the target application processes Unicode strings in a manner that triggers the problematic code path. Attackers can leverage this vulnerability to cause application crashes, potentially leading to service disruption or system instability. In some scenarios, particularly in environments where Python applications are exposed to untrusted input, this vulnerability could be exploited to execute arbitrary code or escalate privileges. The 32-bit platform limitation means that the vulnerability affects older systems where memory addressing constraints make memory corruption more likely to result in exploitable conditions.
Mitigation strategies for CVE-2008-3142 primarily involve immediate application of security patches and updates to Python versions that contain fixes for the Unicode string processing functions. Organizations should prioritize upgrading to Python 2.5.3 or later versions where the memory allocation logic has been corrected to properly handle large Unicode strings. System administrators should implement input validation measures to limit the length of Unicode strings processed by Python applications, particularly in web applications or services that accept user input. The ATT&CK framework categorizes this vulnerability under T1059.006 for Command and Scripting Interpreter, as attackers may use such vulnerabilities to execute malicious code through compromised Python processes. Additionally, defensive measures should include implementing memory protection mechanisms such as stack canaries, address space layout randomization, and heap corruption detection. Network segmentation and application whitelisting can help reduce the attack surface by limiting which systems can interact with vulnerable Python applications. Regular security assessments and vulnerability scanning should be conducted to identify any remaining instances of affected Python versions in the environment, as this vulnerability represents a persistent risk in legacy systems that have not been properly updated.