CVE-2016-5028 in libdwarf
Summary
by MITRE
The print_frame_inst_bytes function in libdwarf before 20160923 allows remote attackers to cause a denial of service (NULL pointer dereference) via an object file with empty bss-like sections.
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Analysis
by VulDB Data Team • 08/15/2020
The vulnerability identified as CVE-2016-5028 represents a critical denial of service flaw within the libdwarf library version prior to 20160923. This issue specifically affects the print_frame_inst_bytes function which processes debug information in object files. The vulnerability arises when the library encounters object files containing empty bss-like sections, creating a scenario where a NULL pointer dereference occurs during normal processing operations. The libdwarf library serves as a crucial component for reading and writing debug information in dwarf format, widely utilized by security tools, debuggers, and system analysis utilities across various operating systems and development environments. This flaw demonstrates the importance of robust input validation in security-critical libraries that handle binary file parsing.
The technical implementation of this vulnerability stems from inadequate null pointer checks within the print_frame_inst_bytes function. When processing object files with empty bss-like sections, the function fails to properly validate section pointers before dereferencing them, leading to a NULL pointer dereference condition. This type of flaw falls under CWE-476 which specifically addresses NULL Pointer Dereference, a common vulnerability pattern that can lead to system instability and denial of service conditions. The vulnerability is particularly concerning because it can be triggered remotely through the processing of maliciously crafted object files, making it exploitable in scenarios where the library processes untrusted input from external sources. The bss section in object files typically contains uninitialized global and static variables, and when these sections are empty, the library's handling becomes problematic.
The operational impact of CVE-2016-5028 extends beyond simple denial of service, as it affects the reliability and stability of systems that depend on libdwarf for debug information processing. Applications that utilize libdwarf for debugging, profiling, or binary analysis can be rendered unresponsive or crash entirely when encountering object files with empty bss sections. This vulnerability affects a wide range of security tools including static analysis tools, reverse engineering frameworks, and system monitoring applications. The attack surface is broad since many security and development tools rely on libdwarf for processing debug information, potentially creating cascading failures across multiple systems and applications. The vulnerability aligns with ATT&CK technique T1499.004 which involves denial of service through resource exhaustion or invalid input handling, making it a significant concern for system administrators and security professionals managing development environments.
Mitigation strategies for CVE-2016-5028 primarily focus on upgrading to libdwarf version 20160923 or later, which contains the necessary patches to address the NULL pointer dereference issue. System administrators should prioritize patching affected systems and applications that utilize libdwarf, particularly those processing external or untrusted binary files. Additional defensive measures include implementing input validation and sanitization protocols for object files before processing, employing sandboxing techniques for binary analysis, and monitoring for unusual resource consumption patterns that might indicate exploitation attempts. Security teams should also consider implementing network segmentation and access controls to limit exposure to potentially malicious object files. The fix implemented in the patched version ensures proper null pointer validation and graceful handling of empty bss-like sections, preventing the crash condition while maintaining full functionality of the library's debug information processing capabilities. Organizations should conduct thorough testing of patched environments to ensure compatibility and verify that the vulnerability has been fully resolved without introducing new issues.