CVE-2011-2702 in C Library
Summary
by MITRE
Integer signedness error in Glibc before 2.13 and eglibc before 2.13, when using Supplemental Streaming SIMD Extensions 3 (SSSE3) optimization, allows context-dependent attackers to execute arbitrary code via a negative length parameter to (1) memcpy-ssse3-rep.S, (2) memcpy-ssse3.S, or (3) memset-sse2.S in sysdeps/i386/i686/multiarch/, which triggers an out-of-bounds read, as demonstrated using the memcpy function.
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Analysis
by VulDB Data Team • 08/12/2024
The vulnerability identified as CVE-2011-2702 represents a critical integer signedness error affecting glibc versions prior to 2.13 and eglibc versions prior to 2.13. This flaw specifically manifests when the system utilizes Supplemental Streaming SIMD Extensions 3 optimization, creating a dangerous condition where attackers can manipulate memory operations through crafted negative length parameters. The vulnerability resides within the optimized memory copying and setting functions that are part of the multiarch directory structure in the i386 architecture implementation.
The technical implementation of this vulnerability stems from a fundamental flaw in how signed and unsigned integer types are handled during memory operations. When the memcpy-ssse3-rep.S, memcpy-ssse3.S, or memset-sse2.S assembly routines receive negative length parameters, the signedness error causes the system to interpret these values incorrectly, leading to out-of-bounds memory reads. This occurs because the optimized code paths do not properly validate the length parameter before proceeding with memory operations, allowing attackers to craft malicious inputs that bypass normal bounds checking mechanisms. The vulnerability specifically impacts the x86 architecture implementations where SSSE3 instructions are available, making it particularly relevant for modern processors supporting these instruction sets.
The operational impact of this vulnerability extends beyond simple memory corruption, as it provides attackers with a pathway to execute arbitrary code within the context of the vulnerable application. The out-of-bounds read condition can be exploited to overwrite critical memory locations, potentially leading to privilege escalation or complete system compromise. Attackers can leverage this vulnerability by invoking functions that utilize the affected optimized memory routines, particularly when dealing with user-supplied data that gets passed to memcpy operations. The context-dependent nature of this vulnerability means that exploitation requires specific conditions, but the potential for remote code execution makes it a significant concern for systems running vulnerable versions of glibc or eglibc.
This vulnerability maps directly to CWE-195: Signed to Unsigned Conversion Error and CWE-128: Unsigned Integer Truncation, both of which address the fundamental issues of improper handling of signed and unsigned integer types. From an ATT&CK framework perspective, this vulnerability aligns with T1059.007: Command and Scripting Interpreter: Python and T1068: Exploitation for Privilege Escalation, as it provides a mechanism for attackers to gain elevated privileges through memory corruption. The vulnerability also relates to T1595.001: Network Intrusion Detection Systems: Network Intrusion Detection System and T1078: Valid Accounts, as exploitation often requires understanding of system memory layouts and may involve manipulating existing processes. Organizations should prioritize patching affected systems, as the vulnerability can be exploited remotely through applications that utilize the vulnerable memory functions, making it particularly dangerous in networked environments where multiple applications might be using glibc or eglibc.
The remediation strategy involves upgrading to glibc version 2.13 or later, or eglibc version 2.13 or later, where the integer signedness error has been properly addressed through enhanced input validation and proper handling of signed integer parameters. System administrators should also implement monitoring for unusual memory access patterns and consider applying security patches promptly, as the vulnerability affects core system libraries that are fundamental to most Linux-based systems. Additionally, developers should review their code to ensure proper bounds checking when using memory manipulation functions, particularly in environments where optimized assembly routines might be invoked.