CVE-2017-7611 in elfutils
Summary
by MITRE
The check_symtab_shndx function in elflint.c in elfutils 0.168 allows remote attackers to cause a denial of service (heap-based buffer over-read and application crash) via a crafted ELF file.
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Analysis
by VulDB Data Team • 11/28/2022
The vulnerability identified as CVE-2017-7611 resides within the elfutils 0.168 library, specifically in the check_symtab_shndx function located in elflint.c. This flaw represents a critical heap-based buffer over-read condition that can be exploited by remote attackers through the deliberate crafting of malicious ELF files. The vulnerability stems from inadequate input validation and bounds checking within the symbol table processing logic of the elflint utility, which is designed to verify the integrity and correctness of elf files. When a malformed ELF file is processed by this utility, the function fails to properly validate array indices or buffer boundaries, leading to memory access violations that result in application crashes.
The technical implementation of this vulnerability involves the manipulation of section header indices within ELF files, specifically targeting the symbol table section. The check_symtab_shndx function processes symbol table entries and their associated section indices without sufficient validation of the input data structure. This allows attackers to craft ELF files containing malformed section index values that exceed the allocated buffer boundaries when the function attempts to access symbol table entries. The heap-based nature of the buffer over-read indicates that the vulnerable memory allocation occurs on the heap rather than the stack, making the exploitation more complex but still highly impactful. The vulnerability falls under the CWE-121 heap-based buffer overflow category, which is classified as a memory safety error that can lead to arbitrary code execution or system instability.
The operational impact of CVE-2017-7611 extends beyond simple denial of service, as it can be leveraged to disrupt critical systems that rely on elflint for file validation and integrity checking. In enterprise environments, this vulnerability could be exploited in automated scanning systems, malware analysis platforms, or build automation tools that process untrusted ELF files. The application crash resulting from this vulnerability can lead to complete system service disruption, particularly when the affected utility is part of automated workflows or security monitoring systems. From an attack perspective, this vulnerability aligns with the ATT&CK technique T1059.007 for execution through command-line interface, as the exploitation typically involves passing malicious ELF files to the vulnerable utility. The vulnerability is particularly concerning in environments where automated file processing occurs, as it can be triggered without user interaction and may affect multiple systems simultaneously.
Mitigation strategies for CVE-2017-7611 should prioritize immediate patching of the elfutils library to version 0.170 or later, where the buffer over-read issue has been resolved through proper bounds checking and input validation. Organizations should implement additional defensive measures including network segmentation to limit exposure of systems running vulnerable versions, deployment of automated file scanning solutions that can identify and quarantine suspicious ELF files before processing, and regular vulnerability assessments to identify other potential instances of similar flaws in the system. Security monitoring should be enhanced to detect unusual patterns of application crashes or memory access violations that may indicate exploitation attempts. The fix implemented in newer versions typically involves adding proper validation of section header indices and implementing bounds checking before array access operations, which directly addresses the root cause of the heap-based buffer over-read condition. System administrators should also consider implementing file format validation at network boundaries and employing sandboxing techniques for processing untrusted ELF files to contain potential exploitation attempts.