CVE-2016-5027 in libdwarf
Summary
by MITRE
dwarf_form.c in libdwarf 20160115 allows remote attackers to cause a denial of service (crash) via a crafted elf file.
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Analysis
by VulDB Data Team • 08/17/2020
The vulnerability identified as CVE-2016-5027 resides within the dwarf_form.c component of libdwarf version 20160115, a widely used library for processing debug information in elf files. This flaw represents a classic buffer over-read condition that can be exploited by remote attackers to trigger a denial of service scenario. The vulnerability manifests when the library processes malformed elf files containing crafted debug information structures that exceed expected boundaries, leading to unpredictable program termination and system instability.
The technical root cause of this vulnerability aligns with CWE-125, which describes out-of-bounds read conditions in software systems. When libdwarf encounters specially crafted elf files with malformed debug information, the dwarf_form.c module fails to properly validate input boundaries before accessing debug attribute data. This occurs during the processing of debug information entries where the library attempts to read beyond allocated memory regions or invalid memory locations within the debug data structure. The flaw specifically impacts the parsing of DW_FORM_* data formats that represent debug information attributes, where insufficient bounds checking allows attackers to manipulate memory access patterns that result in segmentation faults or access violations.
The operational impact of CVE-2016-5027 extends beyond simple service disruption as it can be leveraged in various attack scenarios within the software supply chain and system security landscape. Systems that rely on libdwarf for processing elf files, including software development environments, debuggers, static analysis tools, and security scanning applications, become vulnerable to remote exploitation. The vulnerability can be particularly dangerous in automated build environments, continuous integration systems, or security tools that process untrusted elf files without proper sanitization, potentially allowing attackers to cause widespread service interruptions across multiple systems. This vulnerability also aligns with ATT&CK technique T1059.007 for executing malicious code through debugging interfaces and can be exploited as part of broader attack chains targeting software development infrastructure.
Mitigation strategies for this vulnerability encompass multiple layers of defense including immediate patch application to update libdwarf to versions containing the fix, implementation of input validation mechanisms in applications that utilize the library, and deployment of network-based intrusion detection systems to monitor for exploitation attempts. Organizations should prioritize updating their libdwarf installations to versions released after January 2016, as the vulnerability was addressed through enhanced bounds checking and input validation procedures. Additional protective measures include implementing strict file validation protocols for elf file processing, deploying sandboxing mechanisms for untrusted file analysis, and configuring automated monitoring systems to detect potential exploitation attempts. Security teams should also consider implementing application whitelisting policies to restrict execution of vulnerable applications and establish incident response procedures specifically addressing debug information processing vulnerabilities. The fix typically involves adding comprehensive boundary checks before memory access operations and implementing proper error handling for malformed debug data structures, thereby preventing the out-of-bounds memory access that leads to system crashes and denial of service conditions.