CVE-2016-4490 in libiberty
Summary
by MITRE
Integer overflow in cp-demangle.c in libiberty allows remote attackers to cause a denial of service (segmentation fault and crash) via a crafted binary, related to inconsistent use of the long and int types for lengths.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 02/25/2017
The vulnerability identified as CVE-2016-4490 represents a critical integer overflow flaw within the GNU libiberty library's cp-demangle.c component. This issue specifically manifests when processing demangled C++ symbol names, where the library fails to properly validate length calculations during symbol parsing operations. The flaw arises from inconsistent type usage between long and int data types when handling length parameters, creating conditions where arithmetic operations can exceed maximum representable values for the target integer type. Such overflow conditions result in corrupted memory state during symbol name processing, ultimately leading to segmentation faults and application crashes. The vulnerability impacts any software system that relies on libiberty for symbol demangling operations, including compilers, debuggers, and binary analysis tools that utilize the GNU toolchain components.
The technical implementation of this vulnerability exploits the fundamental weakness in type handling within the demangler's internal processing logic. When parsing complex C++ symbol names, the cp-demangle.c module performs various length calculations to determine buffer allocations and memory boundaries for symbol components. The inconsistency between long and int type declarations creates a scenario where a value that fits within a long integer type may overflow when cast or converted to a 32-bit int type. This overflow condition causes the demangler to allocate insufficient memory buffers or calculate invalid memory addresses, resulting in memory corruption that manifests as segmentation faults during subsequent memory access operations. The vulnerability is particularly dangerous because it can be triggered through malformed binary inputs, making it exploitable in scenarios where applications process untrusted binary data such as object files, executables, or debug symbol information.
From an operational perspective, this vulnerability presents significant risk to systems that depend on libiberty for symbol processing, particularly in development environments, debugging infrastructure, and binary analysis tools. Attackers can craft malicious binary files containing specially constructed symbol names that trigger the integer overflow condition when processed by vulnerable applications. The impact extends beyond simple denial of service, as the segmentation faults can potentially be leveraged to cause application instability or even system crashes in environments where these tools are frequently used. The vulnerability affects a broad range of software components including gcc compilers, gdb debuggers, and various binary analysis utilities that utilize the GNU toolchain. Systems running in production environments where such tools process external binary inputs are particularly vulnerable, as the flaw can be exploited through legitimate use cases without requiring special privileges or complex attack vectors.
Mitigation strategies for CVE-2016-4490 should focus on immediate patching of affected libiberty installations and implementation of input validation measures. Organizations should prioritize updating to libiberty versions containing the fix, which typically involves correcting the type consistency issues in the cp-demangle.c file by ensuring uniform use of appropriate integer types for length calculations. Additionally, implementing input sanitization measures that validate symbol name lengths before processing can provide defense-in-depth protection against malformed inputs. The vulnerability aligns with CWE-190, which describes integer overflow conditions, and demonstrates characteristics consistent with ATT&CK technique T1203, involving the exploitation of software vulnerabilities for denial of service attacks. Security monitoring should include detection of segmentation fault patterns and unusual memory access behaviors when processing binary symbol information, while access controls should limit processing of untrusted binary inputs through automated tools. Regular security audits of toolchain components and dependency management practices can help prevent similar vulnerabilities from being introduced into production environments through the use of outdated or unpatched library versions.