CVE-2016-5044 in libdwarf
Summary
by MITRE
The WRITE_UNALIGNED function in dwarf_elf_access.c in libdwarf before 20160923 allows remote attackers to cause a denial of service (out-of-bounds write and crash) via a crafted DWARF section.
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Analysis
by VulDB Data Team • 08/15/2020
The vulnerability identified as CVE-2016-5044 represents a critical heap-based buffer overflow flaw within the libdwarf library, specifically in the WRITE_UNALIGNED function located in dwarf_elf_access.c. This issue affects versions of libdwarf prior to 20160923 and presents a significant security risk to systems that process DWARF debugging information, particularly those handling untrusted binary files or debugging data. The flaw stems from inadequate bounds checking during the processing of malformed DWARF sections, which are commonly found in executable files, shared libraries, and debug symbol files used in software development and debugging processes.
The technical exploitation of this vulnerability occurs when the WRITE_UNALIGNED function attempts to write data to memory locations without proper validation of the target buffer boundaries. When a maliciously crafted DWARF section is processed, the function fails to verify that the data being written remains within allocated memory boundaries, resulting in an out-of-bounds write operation. This type of vulnerability falls under CWE-787: "Out-of-bounds Write" and represents a classic buffer overflow condition that can be leveraged for denial of service attacks. The vulnerability is particularly concerning because it can be triggered remotely through the processing of untrusted DWARF data, making it applicable to various software systems that utilize libdwarf for debugging information parsing.
The operational impact of CVE-2016-5044 extends beyond simple denial of service, as it can potentially lead to system instability and crashes in applications that depend on libdwarf for processing debugging information. Systems commonly affected include debuggers, static analysis tools, binary analysis frameworks, and software development environments that parse DWARF sections from executable files. The vulnerability can be exploited in environments where applications process user-supplied binaries or debugging data, such as software repositories, code analysis platforms, and automated build systems. According to ATT&CK framework category T1499.004, this vulnerability enables adversaries to perform application denial of service attacks through memory corruption techniques, making it a valuable target for attackers seeking to disrupt system operations.
Mitigation strategies for CVE-2016-5044 primarily involve upgrading to libdwarf version 20160923 or later, which includes proper bounds checking and memory validation in the WRITE_UNALIGNED function. System administrators should prioritize patching affected systems, particularly those handling untrusted binary data or debugging information. Additional protective measures include implementing strict input validation for DWARF data processing, deploying sandboxing mechanisms for binary analysis, and monitoring for unusual system behavior that might indicate exploitation attempts. Organizations should also consider implementing network segmentation and access controls to limit exposure to potentially malicious DWARF data, while maintaining regular vulnerability assessments to identify and remediate similar issues in other system components. The vulnerability demonstrates the importance of robust memory safety practices in security-critical libraries and highlights the need for comprehensive testing of boundary conditions in debugging and analysis tools.