CVE-2017-9053 in libdwarf
Summary
by MITRE
An issue, also known as DW201703-005, was discovered in libdwarf 2017-03-21. A heap-based buffer over-read in _dwarf_read_loc_expr_op() is due to a failure to check a pointer for being in bounds (in a few places in this function).
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Analysis
by VulDB Data Team • 09/30/2020
The vulnerability identified as CVE-2017-9053 represents a critical heap-based buffer over-read flaw within the libdwarf library version 2017-03-21. This issue manifests in the _dwarf_read_loc_expr_op() function where inadequate bounds checking allows for memory access violations that can potentially lead to system instability or exploitation. The vulnerability stems from the failure to validate pointer boundaries in multiple locations within the affected function, creating a scenario where arbitrary memory regions may be accessed beyond their intended limits. This type of flaw falls under the category of memory safety issues commonly classified as CWE-125, which specifically addresses out-of-bounds read conditions that can result in information disclosure, application crashes, or potentially more severe security implications.
The technical implementation of this vulnerability demonstrates a classic buffer over-read pattern where the function processes location expression operations without proper validation of memory pointers before dereferencing them. When libdwarf encounters malformed or specially crafted debug information in dwarf format files, the _dwarf_read_loc_expr_op() function fails to verify that pointer values remain within allocated memory boundaries. This oversight creates a condition where subsequent memory access operations can read data from adjacent memory regions, potentially exposing sensitive information or causing unpredictable behavior in the affected application. The vulnerability is particularly concerning because it operates within a library that is widely used for debugging and analysis purposes, making it a potential attack vector in systems that process untrusted dwarf debug data.
The operational impact of CVE-2017-9053 extends beyond simple application crashes, as it represents a potential pathway for information disclosure and system compromise. When exploited, this vulnerability can cause applications using libdwarf to behave unpredictably, potentially leading to denial of service conditions or data leakage through the over-read operations. The flaw is especially dangerous in environments where debug information from untrusted sources is processed, such as in software development tools, security analysis frameworks, or debugging utilities that parse binary executables containing dwarf debug sections. From an attacker's perspective, this vulnerability aligns with techniques described in the ATT&CK framework under the 'Defense Evasion' and 'Execution' tactics, as it can be leveraged to bypass security controls or execute arbitrary code through memory corruption. The vulnerability's impact is amplified by the widespread use of libdwarf across various security tools and development environments, creating numerous potential attack surfaces.
Mitigation strategies for CVE-2017-9053 should focus on immediate library updates to versions that address the bounds checking deficiencies in _dwarf_read_loc_expr_op(). System administrators and security teams should prioritize patching affected systems, particularly those processing debug information from external or untrusted sources. Additionally, implementing input validation measures and restricting access to debug data can help reduce the attack surface. Organizations should also consider deploying runtime monitoring solutions that can detect anomalous memory access patterns and buffer over-read conditions. The vulnerability serves as a reminder of the critical importance of memory safety practices in security-sensitive libraries and demonstrates how seemingly minor implementation flaws can create significant security risks. Regular security assessments of third-party libraries and maintaining up-to-date dependencies are essential practices to prevent exploitation of similar vulnerabilities in the future.