CVE-2019-7149 in elfutils
Summary
by MITRE
A heap-based buffer over-read was discovered in the function read_srclines in dwarf_getsrclines.c in libdw in elfutils 0.175. A crafted input can cause segmentation faults, leading to denial-of-service, as demonstrated by eu-nm.
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Analysis
by VulDB Data Team • 07/03/2023
The vulnerability identified as CVE-2019-7149 represents a critical heap-based buffer over-read condition within the elfutils library, specifically in the dwarf_getsrclines.c source file at the read_srclines function. This flaw exists in version 0.175 of the elfutils package, which is widely utilized for processing and analyzing executable files and debugging information. The issue manifests when the library processes malformed or crafted input data, particularly in the context of source line information parsing within dwarf debugging sections of executable files. The vulnerability operates at the intersection of binary analysis and memory safety, where improper bounds checking allows an attacker to read beyond allocated heap memory boundaries, potentially exposing sensitive data or causing application instability.
The technical implementation of this vulnerability involves the read_srclines function failing to properly validate input parameters before accessing memory locations. When eu-nm, a tool within the elfutils suite designed for symbol table examination, processes specially crafted binary files containing malformed dwarf debugging information, the function attempts to read source line data beyond the intended buffer limits. This over-read condition can result in segmentation faults due to accessing invalid memory addresses, causing the targeted process to crash and terminate unexpectedly. The flaw demonstrates characteristics consistent with CWE-125, which describes out-of-bounds read vulnerabilities, and may also relate to CWE-787, encompassing out-of-bounds write conditions that can similarly affect heap memory structures. The memory corruption occurs during the parsing of dwarf debugging entries, where source line number information is extracted from executable files for debugging and analysis purposes.
The operational impact of CVE-2019-7149 extends beyond simple denial-of-service conditions, as it can be leveraged to compromise system availability and potentially expose underlying memory contents. Attackers can craft malicious executable files or debug data that, when processed by tools like eu-nm, will trigger the buffer over-read and subsequent segmentation fault. This vulnerability affects any system utilizing the affected version of elfutils, particularly those that process untrusted binary data through debugging tools or symbol analysis utilities. The implications are significant for security analysis environments where tools like eu-nm are routinely used to examine binary files, as an attacker could potentially exploit this condition to disrupt security operations or gain insights into memory layouts. The vulnerability aligns with ATT&CK technique T1059.007, which covers the execution of malicious code through debugging or analysis tools, and demonstrates how seemingly legitimate security utilities can become attack vectors when vulnerable to memory corruption issues.
Mitigation strategies for CVE-2019-7149 focus on immediate patching and version updates to eliminate the vulnerable code path within elfutils 0.175. System administrators should prioritize upgrading to patched versions of elfutils where the buffer over-read has been corrected through proper bounds checking and input validation mechanisms. Additionally, organizations should implement input sanitization measures when processing untrusted binary data through debugging tools, including sandboxing operations and restricting tool usage to trusted sources. The vulnerability highlights the importance of memory safety practices in security-critical libraries and underscores the need for comprehensive testing of edge cases in binary parsing functions. Security monitoring should include detection of segmentation faults and abnormal process termination patterns when using elfutils tools, as these may indicate exploitation attempts. Regular vulnerability assessments of system libraries and security toolchains remain essential to prevent similar issues from compromising system integrity and availability.