CVE-2016-5029 in libdwarf
Summary
by MITRE
The create_fullest_file_path function in libdwarf before 20160923 allows remote attackers to cause a denial of service (NULL pointer dereference) via a crafted dwarf file.
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Analysis
by VulDB Data Team • 08/15/2020
The vulnerability identified as CVE-2016-5029 represents a critical denial of service flaw within the libdwarf library version prior to 20160923. This library serves as a fundamental component for processing debug information in dwarf format, widely utilized in software development and security analysis tools. The issue stems from the create_fullest_file_path function which fails to properly validate input parameters when processing malformed dwarf files, creating an exploitable condition that can be leveraged by remote attackers to disrupt system operations. The vulnerability manifests as a NULL pointer dereference, a common class of software defects that occurs when a program attempts to access memory through a null reference, leading to abrupt program termination and system instability.
The technical implementation of this vulnerability involves the improper handling of file path construction within the dwarf debugging information parser. When a maliciously crafted dwarf file is processed, the create_fullest_file_path function receives malformed input that causes internal pointer variables to remain uninitialized or set to NULL values. This condition violates fundamental programming practices and security principles, as the function does not implement proper input validation or error checking mechanisms. The flaw aligns with CWE-476 which specifically addresses NULL pointer dereference conditions, representing a well-documented weakness in software development practices that has been consistently identified in security assessments and penetration testing activities. The vulnerability can be exploited through various attack vectors including file upload mechanisms, network-based processing of debug information, or when applications process untrusted dwarf data streams.
The operational impact of CVE-2016-5029 extends beyond simple service disruption to encompass broader system reliability and availability concerns. Remote attackers can leverage this vulnerability to systematically crash applications that depend on libdwarf for debug information processing, potentially affecting development environments, security analysis tools, and system monitoring applications. This denial of service condition can be particularly problematic in production environments where debug information processing is integral to application performance monitoring, security auditing, and forensic analysis operations. The vulnerability's exploitation does not require authentication or special privileges, making it accessible to any remote attacker who can submit crafted dwarf files to vulnerable systems. From an attack framework perspective, this vulnerability aligns with techniques described in the ATT&CK matrix under the T1499 category for network denial of service attacks, where adversaries target application-level vulnerabilities to disrupt system availability.
Mitigation strategies for this vulnerability primarily focus on immediate remediation through library updates and implementation of defensive programming practices. System administrators should prioritize updating to libdwarf version 20160923 or later, which contains the necessary patches to address the NULL pointer dereference condition. Additionally, organizations should implement input validation controls and sandboxing mechanisms when processing debug information from untrusted sources. The vulnerability demonstrates the importance of proper error handling and defensive programming techniques, emphasizing the need for comprehensive testing procedures including fuzzing and input validation testing. Security teams should also consider implementing network-based detection mechanisms to identify potential exploitation attempts and establish monitoring protocols for unusual application termination patterns that may indicate successful exploitation of this vulnerability.