CVE-2016-5032 in libdwarf
Summary
by MITRE
The dwarf_get_xu_hash_entry function in libdwarf before 20160923 allows remote attackers to cause a denial of service (crash) via a crafted file.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 08/15/2020
The vulnerability identified as CVE-2016-5032 resides within the libdwarf library, a critical component used for processing debug information in binary files, particularly in the context of software development and reverse engineering activities. This library serves as an essential tool for developers and security researchers who need to analyze executable files and understand their internal structure. The specific flaw is located in the dwarf_get_xu_hash_entry function, which is responsible for handling hash table operations when processing debug information. This function processes data structures that map debug information entries to their corresponding hash values, making it a crucial element in the library's operation. The vulnerability becomes particularly concerning when considering that libdwarf is widely used across various operating systems and software applications, including system utilities, compilers, and security analysis tools that rely on proper debug information handling.
The technical nature of this vulnerability stems from insufficient input validation within the dwarf_get_xu_hash_entry function, which fails to properly validate the structure and content of debug information entries before processing them. When a maliciously crafted file containing malformed debug information is processed by the library, the function attempts to access memory locations or perform operations on data structures that have not been properly initialized or validated. This leads to a crash condition that manifests as a segmentation fault or similar memory access violation, causing the application that utilizes libdwarf to terminate unexpectedly. The vulnerability represents a classic example of a buffer over-read or improper input validation issue, where the function does not adequately check the bounds of input data or the validity of hash table entries before attempting to access them. According to CWE classification, this vulnerability maps to CWE-125, which describes an out-of-bounds read condition, and potentially CWE-787, which covers out-of-bounds write conditions, depending on the specific execution path taken during processing.
The operational impact of CVE-2016-5032 extends beyond simple denial of service, as it can be leveraged by remote attackers to disrupt services that depend on libdwarf functionality. Any application or system that processes binary files containing debug information, such as package managers, system analyzers, or security tools, becomes vulnerable to this attack vector. The vulnerability is particularly dangerous in environments where automated processing of user-supplied files occurs, as attackers could craft malicious files that trigger the crash when processed by legitimate applications. This creates a potential for widespread disruption across multiple software ecosystems, as the library is integrated into numerous system components and third-party applications. From an ATT&CK framework perspective, this vulnerability aligns with the T1499.004 technique related to network denial of service attacks, where the attacker leverages a flaw in a software library to cause service disruption. The attack requires minimal privileges and can be executed remotely, making it a particularly attractive vector for adversaries seeking to disrupt system availability.
Mitigation strategies for this vulnerability primarily focus on updating to the patched version of libdwarf released in September 2016, which contains proper input validation and bounds checking mechanisms. System administrators and software vendors should prioritize patching affected systems and applications that utilize libdwarf, particularly those handling untrusted binary input. Additionally, implementing proper input sanitization at the application level can provide defense-in-depth measures, where applications can validate debug information before passing it to libdwarf functions. Network-level protections such as file type validation and content inspection can help prevent malicious files from reaching systems that process debug information. Organizations should also consider implementing monitoring and alerting mechanisms to detect unusual crash patterns or service disruptions that might indicate exploitation attempts. The vulnerability highlights the importance of maintaining up-to-date security libraries and implementing comprehensive security testing procedures that include fuzzing and input validation checks for all components that process external data, particularly in security-critical applications.