CVE-2018-8769 in elfutils
Summary
by MITRE
elfutils 0.170 has a buffer over-read in the ebl_dynamic_tag_name function of libebl/ebldynamictagname.c because SYMTAB_SHNDX is unsupported.
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Analysis
by VulDB Data Team • 01/14/2020
The vulnerability identified as CVE-2018-8769 represents a critical buffer over-read flaw within the elfutils library version 0.170, specifically affecting the ebl_dynamic_tag_name function located in libebl/ebldynamictagname.c. This issue arises from the library's inability to properly handle the SYMTAB_SHNDX dynamic tag, which is a specialized section header index that appears in certain ELF (Executable and Linkable Format) files. The flaw occurs when the function attempts to process dynamic tags in ELF binaries that contain this unsupported tag, leading to memory access violations that can potentially be exploited by malicious actors.
The technical nature of this vulnerability stems from inadequate input validation and boundary checking within the ebl_dynamic_tag_name function. When processing ELF files containing SYMTAB_SHNDX tags, the function does not properly verify the bounds of memory accesses, causing it to read beyond the allocated buffer space. This over-read condition manifests as a classic buffer overflow vulnerability that falls under the CWE-121 category of buffer overflow conditions. The flaw is particularly dangerous because it can occur during normal operation of tools that process ELF files, such as debuggers, system analyzers, or security assessment utilities that rely on elfutils for binary analysis.
The operational impact of CVE-2018-8769 extends beyond simple memory corruption, as it can lead to application crashes, denial of service conditions, and potentially more severe consequences when exploited in targeted attacks. Systems that utilize elfutils for processing ELF binaries, including those running security tools, system monitoring applications, or development environments, become vulnerable to this flaw. The vulnerability is particularly concerning in environments where untrusted ELF files are processed, as attackers could craft malicious binaries specifically designed to trigger this buffer over-read condition. This scenario aligns with ATT&CK technique T1059.007 for execution through scripting and could be leveraged for privilege escalation or information disclosure attacks.
Mitigation strategies for CVE-2018-8769 should focus on immediate patching of the elfutils library to version 0.171 or later, which contains the necessary fixes for handling SYMTAB_SHNDX tags. System administrators should also implement input validation measures when processing ELF files from untrusted sources, including implementing sandboxed environments for binary analysis and employing static analysis tools that can detect potentially malicious ELF structures. Additionally, monitoring systems should be configured to detect unusual memory access patterns or application crashes that may indicate exploitation attempts. The fix implemented in the patched versions typically involves proper bounds checking and conditional handling of unsupported dynamic tags, ensuring that memory accesses remain within valid buffer boundaries and preventing the over-read condition that leads to potential exploitation.