CVE-2016-5038 in libdwarf
Summary
by MITRE
The dwarf_get_macro_startend_file function in dwarf_macro5.c in libdwarf before 20160923 allows remote attackers to cause a denial of service (out-of-bounds read) via a crafted string offset for .debug_str.
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Analysis
by VulDB Data Team • 08/15/2020
The vulnerability identified as CVE-2016-5038 represents a critical out-of-bounds read flaw within the libdwarf library's dwarf_get_macro_startend_file function located in dwarf_macro5.c. This issue affects versions of libdwarf prior to 20160923 and presents a significant security risk that can be exploited by remote attackers to execute denial of service attacks. The vulnerability specifically manifests when processing crafted string offsets within the .debug_str section of debug information files, which are commonly found in executable binaries and shared libraries used in software development and debugging processes.
The technical nature of this flaw stems from insufficient input validation and bounds checking within the dwarf_get_macro_startend_file function. When libdwarf processes debug information containing maliciously crafted string offsets in the .debug_str section, the function fails to properly validate the boundaries of memory access operations. This allows an attacker to provide a specially crafted offset value that exceeds the legitimate bounds of the debug string data structure, resulting in an out-of-bounds memory read operation that can cause program termination or unpredictable behavior. The vulnerability operates at the binary analysis level where debug information is parsed and interpreted, making it particularly dangerous as it can affect any application that utilizes libdwarf for processing debug data, including development tools, system utilities, and security analysis software.
The operational impact of CVE-2016-5038 extends beyond simple denial of service conditions as it can disrupt legitimate debugging and analysis workflows across various software development environments. Attackers can exploit this vulnerability by crafting malicious debug information files or manipulating existing debug data in ways that trigger the out-of-bounds read condition. The vulnerability affects systems that process or analyze binary executables containing debug information, including build systems, static analysis tools, debuggers, and security scanning applications. This creates a substantial risk for software development environments where debug information is routinely processed and can potentially be manipulated by untrusted inputs. The flaw can be particularly problematic in continuous integration environments or automated build processes where debug information is automatically parsed and analyzed without proper validation of input data integrity.
Organizations and developers should implement immediate mitigations including updating to libdwarf versions released after September 23, 2016, which contain the necessary patches to address this vulnerability. System administrators should also consider implementing input validation controls and sandboxing measures when processing debug information from untrusted sources. The vulnerability aligns with CWE-129, which describes improper validation of array indices, and can be mapped to ATT&CK technique T1059.007 for the execution of malicious code through manipulation of debug information. Additionally, security professionals should monitor for potential exploitation attempts through automated scanning tools that may attempt to trigger this vulnerability in systems processing debug data. The remediation process should include comprehensive testing of updated libraries to ensure that the fix does not introduce regressions in legitimate debugging functionality while maintaining the security improvements necessary to prevent exploitation.