CVE-2012-3480 in C Library
Summary
by MITRE
Multiple integer overflows in the (1) strtod, (2) strtof, (3) strtold, (4) strtod_l, and other unspecified "related functions" in stdlib in GNU C Library (aka glibc or libc6) 2.16 allow local users to cause a denial of service (application crash) and possibly execute arbitrary code via a long string, which triggers a stack-based buffer overflow.
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Analysis
by VulDB Data Team • 10/15/2024
The vulnerability identified as CVE-2012-3480 represents a critical security flaw within the GNU C Library implementation of floating-point conversion functions. This issue affects multiple core functions including strtod, strtof, strtold, and their localized variants, which are fundamental components used throughout Unix-like operating systems for converting string representations of numbers into floating-point values. The flaw stems from improper handling of integer overflow conditions during the parsing of extremely long numeric strings, creating a pathway for malicious input to trigger system instability.
The technical root cause of this vulnerability lies in the integer overflow conditions that occur when processing exceptionally long string inputs within the floating-point conversion routines. When these functions encounter strings that exceed normal processing limits, they fail to properly validate the length of input data before performing calculations that determine buffer allocation sizes. This leads to situations where integer arithmetic results in values that exceed the maximum representable integer, causing subsequent buffer overflow conditions. The vulnerability manifests as stack-based buffer overflows due to inadequate bounds checking in the memory allocation logic, where the system attempts to allocate memory based on corrupted integer calculations derived from the malformed input strings.
The operational impact of CVE-2012-3480 extends beyond simple denial of service scenarios to potentially enable arbitrary code execution on vulnerable systems. Local attackers can exploit this vulnerability by providing carefully crafted long string inputs to applications that rely on glibc's floating-point conversion functions, leading to application crashes or system instability. The attack vector is particularly concerning because these functions are extensively used across numerous system utilities, applications, and services, meaning a single vulnerable function call can compromise multiple components. The vulnerability maps directly to CWE-190, which describes integer overflow conditions, and aligns with ATT&CK techniques related to privilege escalation and code execution through software exploitation.
Mitigation strategies for this vulnerability require immediate patching of affected glibc versions, with system administrators prioritizing updates to glibc 2.17 or later releases that contain the necessary fixes. Organizations should also implement input validation controls at application boundaries to sanitize numeric string inputs before they reach the vulnerable functions, reducing the attack surface. Additionally, system monitoring should be enhanced to detect unusual patterns of function calls that might indicate exploitation attempts, particularly focusing on applications that process user-provided numeric data. The remediation approach should follow industry best practices for vulnerability management as outlined in NIST guidelines, ensuring comprehensive coverage across all systems utilizing affected glibc versions while maintaining operational continuity through proper testing and deployment procedures.