CVE-2018-9138 in binutils
Summary
by MITRE
An issue was discovered in cplus-dem.c in GNU libiberty, as distributed in GNU Binutils 2.29 and 2.30. Stack Exhaustion occurs in the the C++ demangling functions provided by libiberty, and there are recursive stack frames: demangle_nested_args, demangle_args, do_arg, and do_type.
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Analysis
by VulDB Data Team • 02/24/2023
The vulnerability identified as CVE-2018-9138 represents a critical stack exhaustion issue within GNU libiberty's C++ demangling functionality, specifically affecting GNU Binutils versions 2.29 and 2.30. This flaw exists in the cplus-dem.c file where recursive function calls create an exploitable condition that can lead to denial of service or potential code execution. The vulnerability stems from the demangle_nested_args, demangle_args, do_arg, and do_type functions which form a recursive call chain that can be triggered through malformed input during C++ symbol demangling operations.
The technical implementation of this vulnerability exploits the recursive nature of the demangling functions without adequate stack depth protection or input validation. When processing specially crafted C++ symbols, these functions can recursively call themselves multiple times, consuming stack space rapidly and eventually leading to stack exhaustion. The recursive pattern creates a potential for unbounded stack growth where each function call adds a new stack frame, and the depth of recursion is directly proportional to the complexity of the input symbol being processed. This behavior aligns with CWE-674, which describes the issue of uncontrolled recursion leading to stack overflow conditions.
From an operational perspective, this vulnerability poses significant risks to systems that process C++ symbols or binaries containing such symbols, particularly in environments where GNU Binutils is used for debugging, reverse engineering, or binary analysis. Attackers could potentially exploit this by providing maliciously constructed C++ symbols to trigger the recursive demangling process, causing applications that rely on libiberty to crash or become unresponsive. The impact extends beyond simple denial of service as the vulnerability could potentially be leveraged in more sophisticated attacks depending on the execution context where the vulnerable functions are called.
The vulnerability demonstrates a classic example of insufficient recursion depth checking and input validation in system libraries, making it particularly dangerous in applications that process untrusted input through the demangling functionality. Systems utilizing GNU Binutils for symbol resolution, debugging, or binary analysis are at risk, especially when these tools are used in security-sensitive contexts or when processing input from untrusted sources. The flaw affects the fundamental operation of symbol demangling which is critical for debugging and analysis tools, making it a high-impact vulnerability in development and security toolchains.
Mitigation strategies for CVE-2018-9138 should focus on immediate patching of affected GNU Binutils versions to the corrected releases that address the recursive stack exhaustion issue. Organizations should also implement input validation measures when processing C++ symbols or binaries, particularly in applications that interface with libiberty functions. Additional protective measures include monitoring for unusual stack consumption patterns in applications using these libraries, implementing stack depth limits, and considering sandboxing approaches for processing untrusted binary input. The vulnerability highlights the importance of proper recursion handling and stack management in system libraries, aligning with ATT&CK technique T1499.004 which covers the use of resource exhaustion attacks against system services.