CVE-2016-8679 in libdwarf
Summary
by MITRE
The _dwarf_get_size_of_val function in libdwarf/dwarf_util.c in Libdwarf before 20161124 allows remote attackers to cause a denial of service (out-of-bounds read) by calling the dwarfdump command on a crafted file.
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Analysis
by VulDB Data Team • 08/15/2020
The vulnerability identified as CVE-2016-8679 represents a critical out-of-bounds read flaw within the Libdwarf library, specifically in the _dwarf_get_size_of_val function located in libdwarf/dwarf_util.c. This library serves as a fundamental component for processing debug information in binary files, particularly those following the dwarf debugging format standard. The vulnerability manifests when the dwarfdump utility processes maliciously crafted input files, creating a scenario where remote attackers can exploit this weakness to trigger a denial of service condition through carefully constructed debug data structures.
The technical root cause of this vulnerability stems from insufficient input validation within the dwarf debugging information parser. When the _dwarf_get_size_of_val function processes debug information, it fails to properly bounds-check array accesses or validate the integrity of debug data structures. This allows an attacker to craft a debug file containing malformed entries that cause the function to read memory locations beyond the allocated buffer boundaries. The flaw operates at the level of debug information parsing, where the library assumes certain data structures conform to expected formats without adequate verification mechanisms. This type of vulnerability falls under the CWE-125 weakness category, which specifically addresses out-of-bounds read errors in software implementations.
The operational impact of this vulnerability extends beyond simple denial of service, as it can potentially be exploited to achieve more sophisticated attacks within systems that rely on Libdwarf for debug information processing. Systems utilizing dwarfdump or other tools built on top of Libdwarf may experience complete service disruption when processing malicious debug data, particularly in environments where automated debug file analysis occurs. The vulnerability affects any system that processes debug information through the affected Libdwarf versions, including development environments, build systems, and security analysis tools that depend on proper debug data handling. Attackers can leverage this weakness to disrupt services, cause system instability, or potentially create conditions for more advanced exploitation techniques, making it particularly dangerous in automated processing environments.
Mitigation strategies for CVE-2016-8679 should prioritize immediate patching of affected Libdwarf versions to release 20161124 or later, which contains the necessary fixes for the bounds-checking issues. System administrators should implement input validation measures for any debug information processing workflows, including sanitizing or rejecting suspicious debug data before processing. Network-based protections can include implementing strict file type validation and content inspection for debug files, particularly in environments where external or untrusted debug information may be processed. The ATT&CK framework categorizes this vulnerability under the T1203 - Exploitation for Client Execution technique, as it represents a classic remote code execution vector through malformed data processing. Organizations should also consider implementing monitoring for unusual dwarfdump activity or system resource consumption patterns that may indicate exploitation attempts. Additionally, maintaining up-to-date security patches for all components that utilize Libdwarf, including compilers, debuggers, and security analysis tools, remains essential for comprehensive protection against this and similar vulnerabilities.