CVE-2012-2674 in bionic
Summary
by MITRE
Multiple integer overflows in the (1) chk_malloc, (2) leak_malloc, and (3) leak_memalign functions in libc/bionic/malloc_debug_leak.c in Bionic (libc) for Android, when libc.debug.malloc is set, make it easier for context-dependent attackers to perform memory-related attacks such as buffer overflows via a large size value, which causes less memory to be allocated than expected.
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Analysis
by VulDB Data Team • 12/07/2021
The vulnerability described in CVE-2012-2674 represents a critical integer overflow issue within the Bionic libc library implementation for Android systems. This flaw exists specifically in the memory allocation debugging functions chk_malloc, leak_malloc, and leak_memalign located in libc/bionic/malloc_debug_leak.c. When the system property libc.debug.malloc is enabled, these functions become active and susceptible to exploitation through improper integer overflow handling. The vulnerability manifests when attackers provide large size values to these memory allocation functions, causing the system to allocate insufficient memory compared to what was requested, creating conditions ripe for memory corruption attacks.
The technical nature of this vulnerability stems from improper handling of integer arithmetic within the debugging malloc functions. When large allocation requests are processed, the integer overflow occurs during the calculation of memory requirements, leading to a situation where the actual memory allocated is significantly less than the requested amount. This discrepancy creates a dangerous condition where subsequent memory operations may overwrite adjacent memory regions, potentially leading to buffer overflows, arbitrary code execution, or other memory corruption attacks. The flaw operates at the intersection of memory management and integer arithmetic, making it particularly insidious as it leverages legitimate debugging functionality to create exploitable conditions.
The operational impact of this vulnerability extends beyond simple memory allocation failures, as it directly enables context-dependent attackers to perform sophisticated memory-related attacks. Attackers can exploit this weakness by crafting malicious allocation requests with carefully calculated large values that trigger the integer overflow, resulting in insufficient memory allocation that can be manipulated to overwrite critical data structures or execute arbitrary code. The vulnerability is particularly dangerous in Android environments where applications may be running with elevated privileges or where memory corruption could lead to complete system compromise. This issue affects the fundamental memory management capabilities of Android systems when debugging features are enabled, potentially undermining the security posture of mobile devices.
Security mitigations for this vulnerability require immediate attention and should include disabling the libc.debug.malloc system property when not actively debugging, as this prevents the vulnerable code paths from being executed. System administrators and developers should also implement proper input validation and bounds checking for all memory allocation requests, ensuring that large values are properly sanitized before being processed by malloc functions. The vulnerability aligns with CWE-190, Integer Overflow or Wraparound, and represents a classic example of how debugging features can introduce security weaknesses when not properly secured. Additionally, this issue maps to ATT&CK technique T1059.007 for executing malicious code through memory corruption, and T1068 for privilege escalation through memory management flaws, highlighting its potential for broader exploitation across different attack vectors.