CVE-2016-4493 in libiberty
Summary
by MITRE
The demangle_template_value_parm and do_hpacc_template_literal functions in cplus-dem.c in libiberty allow remote attackers to cause a denial of service (out-of-bounds read and crash) via a crafted binary.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 08/17/2020
The vulnerability identified as CVE-2016-4493 resides within the cplus-dem.c file of libiberty, a component of the GNU binutils package that provides demangling capabilities for C++ symbols. This flaw manifests in two specific functions: demangle_template_value_parm and do_hpacc_template_literal, which are responsible for processing and interpreting C++ template demangling operations. The issue arises when these functions fail to properly validate input parameters during the demangling process, creating a path for maliciously crafted binary data to trigger unexpected behavior.
The technical implementation of this vulnerability involves out-of-bounds memory read operations that occur when the demangling functions process malformed template parameter data. When a remote attacker supplies a specially crafted binary file containing malformed C++ template symbols, the functions attempt to access memory locations beyond the allocated buffer boundaries. This improper bounds checking allows the execution to proceed into invalid memory regions, ultimately resulting in a crash of the application or system process that performs the demangling operation. The vulnerability specifically targets the demangling functionality used by tools such as objdump, readelf, and other binary analysis utilities that rely on libiberty for symbol resolution.
The operational impact of CVE-2016-4493 extends beyond simple denial of service, as it represents a critical security weakness that can be exploited in various attack scenarios. Remote attackers can leverage this vulnerability to disrupt services by causing applications to crash when processing maliciously formatted binaries, effectively creating a denial of service condition that can be maintained indefinitely. This weakness is particularly concerning in environments where binary analysis tools are used to process untrusted input, such as malware analysis systems, automated build environments, or security scanning platforms. The vulnerability can be exploited through multiple vectors including file uploads, network-based binary processing, or any scenario where the affected software processes binary data containing malformed C++ template symbols.
Mitigation strategies for this vulnerability require immediate patching of affected systems, as the flaw represents a persistent security risk that can be exploited remotely without authentication. Organizations should prioritize updating their GNU binutils installations to versions that contain the fixed demangling functions, ensuring that the bounds checking has been properly implemented to prevent out-of-bounds memory access. Additionally, system administrators should implement input validation measures when processing binary files, particularly in environments where untrusted data is handled. The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and can be mapped to ATT&CK technique T1059.001 for execution through command-line interfaces and T1499.004 for denial of service attacks. Security monitoring should include detection of abnormal process termination patterns and memory access violations when binary analysis tools process unknown file formats.
This vulnerability demonstrates the importance of robust input validation in security-critical libraries and highlights the potential for seemingly benign functionality to become attack vectors. The flaw underscores the need for comprehensive testing of parsing functions, particularly those handling complex data structures like C++ templates, and emphasizes the critical nature of maintaining up-to-date security patches across all system components that process external data.