CVE-2016-5043 in libdwarf
Summary
by MITRE
The dwarf_dealloc function in libdwarf before 20160923 allows remote attackers to cause a denial of service (out-of-bounds read and crash) via a crafted DWARF section.
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Analysis
by VulDB Data Team • 08/15/2020
The vulnerability identified as CVE-2016-5043 affects the libdwarf library version prior to 20160923, presenting a critical security risk that enables remote attackers to execute denial of service attacks through out-of-bounds read operations. This flaw specifically targets the dwarf_dealloc function, which is responsible for memory deallocation within the DWARF debugging information format processing subsystem. The vulnerability arises from insufficient input validation and boundary checking when processing malformed DWARF sections, creating a scenario where maliciously crafted debugging data can trigger unpredictable behavior in applications that utilize libdwarf for processing binary files.
The technical implementation of this vulnerability stems from improper handling of DWARF section data structures during memory deallocation operations. When libdwarf encounters a malformed DWARF section containing crafted data, the dwarf_dealloc function fails to properly validate array indices or section boundaries before accessing memory locations. This results in out-of-bounds memory reads that can lead to application crashes, segmentation faults, or other forms of system instability. The flaw operates at the intersection of software security and memory management, where the absence of proper bounds checking allows attackers to manipulate memory access patterns and cause unintended program termination.
From an operational perspective, this vulnerability poses significant risks to systems that rely on libdwarf for processing binary files, particularly in environments where applications handle untrusted input such as file analysis tools, debuggers, binary scanners, and software development environments. The remote exploitation capability means that attackers can trigger the vulnerability without requiring local access, making it particularly dangerous for web applications, file upload systems, or any service that processes user-provided binary content. The impact extends beyond simple service disruption to potentially compromising the availability of critical debugging and analysis tools that security professionals depend upon.
The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and represents a classic example of memory safety issues that have plagued software development for decades. From the MITRE ATT&CK framework perspective, this vulnerability could be leveraged as part of a broader attack chain where initial access is achieved through file-based exploits, followed by privilege escalation or further system compromise. Organizations should prioritize immediate patching of affected systems, as the vulnerability does not require complex exploitation techniques and can be triggered through simple malformed input. Additionally, implementing input validation controls, sandboxing mechanisms, and regular security assessments of third-party libraries can help mitigate the risk of similar vulnerabilities in other components of the software supply chain.
The remediation strategy involves upgrading to libdwarf version 20160923 or later, which includes proper bounds checking and input validation mechanisms. System administrators should also consider implementing network segmentation, access controls, and monitoring solutions to detect potential exploitation attempts. Regular vulnerability scanning and penetration testing should be conducted to identify other potentially affected components that may use similar memory handling patterns. The incident serves as a reminder of the critical importance of maintaining up-to-date security patches and the need for comprehensive security testing of all third-party libraries and components used in production environments.