CVE-2016-5040 in libdwarf
Summary
by MITRE
libdwarf before 20160923 allows remote attackers to cause a denial of service (out-of-bounds read and crash) via a large length value in a compilation unit header.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 08/15/2020
The vulnerability identified as CVE-2016-5040 affects the libdwarf library version prior to 20160923, presenting a critical security flaw that enables remote attackers to execute denial of service attacks through carefully crafted input data. This issue manifests when the library processes a compilation unit header containing an excessively large length value, leading to out-of-bounds memory read operations and subsequent system crashes. The libdwarf library serves as a crucial component for parsing debug information in binary files, particularly within software development and security analysis tools that rely on DWARF debugging format support. The vulnerability stems from inadequate input validation mechanisms within the library's parsing routines, specifically failing to properly validate the length field in compilation unit headers before proceeding with memory operations. This flaw represents a classic example of insufficient bounds checking, which aligns with CWE-129, representing an out-of-bounds read vulnerability that occurs when a program attempts to access memory beyond the allocated buffer boundaries. The operational impact of this vulnerability extends beyond simple service disruption, as it can compromise the stability of applications and systems that depend on libdwarf for processing debug information, particularly in environments where binary analysis tools are extensively used.
The technical exploitation of this vulnerability requires an attacker to craft a malformed debug information file containing an oversized length value in a compilation unit header, which when processed by the vulnerable libdwarf library triggers the out-of-bounds read condition. The library's failure to validate the length parameter before using it to determine memory allocation or access patterns creates a predictable crash scenario that can be reliably reproduced. This behavior follows attack patterns consistent with the ATT&CK framework's privilege escalation and denial of service tactics, where adversaries leverage software weaknesses to disrupt system availability. The vulnerability is particularly concerning because it affects a widely used library that supports numerous security tools, development environments, and binary analysis frameworks, making the potential attack surface extensive. When the malformed input is processed, the library attempts to read memory beyond its intended boundaries, causing segmentation faults and system crashes that can be exploited to deny service to legitimate users and applications relying on the affected software stack.
Mitigation strategies for CVE-2016-5040 primarily focus on immediate remediation through library updates to versions released after September 23, 2016, which contain proper input validation and bounds checking mechanisms. System administrators and security teams should prioritize patching all affected systems that utilize libdwarf, particularly those running security analysis tools, debuggers, or binary analysis frameworks that depend on this library. Additionally, implementing input sanitization measures at the application level can provide defense-in-depth protection, ensuring that any debug information processed through libdwarf is validated before being passed to the vulnerable parsing routines. Organizations should also consider monitoring for suspicious binary files or debug information that may contain malformed compilation unit headers, as part of their broader security operations and threat detection protocols. The vulnerability's classification as a denial of service issue underscores the importance of maintaining up-to-date software libraries and implementing proper security testing procedures that include fuzzing and input validation testing to identify similar boundary condition flaws in other software components.