CVE-2016-5036 in libdwarf
Summary
by MITRE
The dump_block function in print_sections.c in libdwarf before 20160923 allows remote attackers to cause a denial of service (out-of-bounds read) via crafted frame data.
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Analysis
by VulDB Data Team • 08/15/2020
The vulnerability identified as CVE-2016-5036 resides within the libdwarf library, specifically in the dump_block function located in print_sections.c. This library serves as a critical component for parsing and processing dwarf debugging information in executable files, commonly used in software development, debugging, and security analysis tools. The flaw manifests when the library processes malformed frame data, creating a scenario where remote attackers can exploit the system through crafted input that triggers an out-of-bounds read condition. This type of vulnerability falls under the category of memory safety issues and represents a classic example of insufficient input validation that can lead to system instability and potential denial of service conditions.
The technical implementation of this vulnerability stems from inadequate bounds checking within the dump_block function, which is responsible for processing and displaying section data from debug information. When the function encounters malformed frame data, it fails to properly validate array indices or buffer limits before accessing memory locations. This oversight allows attackers to craft specially designed frame data that causes the function to read memory beyond its allocated boundaries. The out-of-bounds read can result in unpredictable behavior including program crashes, data corruption, or potentially information disclosure depending on the memory layout and access patterns. This vulnerability directly maps to CWE-125: Out-of-bounds Read, which is categorized under the broader weakness of insufficient input validation in memory safety contexts. The issue demonstrates how debugging information parsers can become attack vectors when proper input sanitization is not implemented.
The operational impact of CVE-2016-5036 extends beyond simple denial of service scenarios, as it represents a potential pathway for more sophisticated attacks within software supply chain and security analysis contexts. Systems that rely on libdwarf for processing debug information, such as security scanners, forensic analysis tools, or debugging frameworks, become vulnerable to remote exploitation when processing maliciously crafted binaries. The vulnerability can be particularly dangerous in environments where automated tools continuously process unknown or untrusted binaries, as it can lead to system-wide denial of service across multiple applications that depend on the affected library. Attackers could leverage this vulnerability to disrupt services, consume system resources through repeated exploitation attempts, or potentially gain insights into memory structures through information leakage. This aligns with ATT&CK technique T1059.007: Command and Scripting Interpreter: Python, where improper input handling in library components can lead to execution of unintended code paths. The vulnerability's remote exploitability means that systems processing debug information from network sources or untrusted binaries could be compromised without direct user interaction.
Mitigation strategies for CVE-2016-5036 should focus on immediate library updates to versions released after September 23, 2016, when the vulnerability was patched. Organizations should conduct comprehensive inventory assessments to identify all systems and applications that utilize libdwarf, particularly those involved in security analysis, debugging, or binary processing workflows. The patch implementation should include thorough regression testing to ensure that the updated library maintains compatibility with existing tools and workflows. Additionally, implementing defensive programming practices such as bounds checking, input validation, and memory safety mechanisms should be enforced in all codebases that process external data. System administrators should consider deploying intrusion detection systems that monitor for unusual patterns of memory access or denial of service attempts, while also implementing network segmentation to limit exposure of systems processing untrusted binary data. Regular security audits and vulnerability assessments should be conducted to identify similar memory safety issues in other third-party libraries and components, as this vulnerability demonstrates how debugging and analysis tools can become attack surfaces when proper security controls are not implemented.