CVE-2019-14249 in libdwarf
Summary
by MITRE
dwarf_elf_load_headers.c in libdwarf before 2019-07-05 allows attackers to cause a denial of service (division by zero) via an ELF file with a zero-size section group (SHT_GROUP), as demonstrated by dwarfdump.
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Analysis
by VulDB Data Team • 11/06/2023
The vulnerability described in CVE-2019-14249 represents a critical denial of service weakness within the libdwarf library, specifically in the dwarf_elf_load_headers.c component. This flaw manifests when processing ELF files containing a zero-size section group with the SHT_GROUP type, creating a scenario where the software attempts to perform a division by zero operation during header loading procedures. The issue affects libdwarf versions prior to the 2019-07-05 release, making it a significant concern for systems relying on this library for debugging and development tooling. The vulnerability is particularly dangerous because it can be triggered by simply providing a malformed ELF file to tools that depend on libdwarf, such as dwarfdump, which is commonly used for examining debug information within executable files.
The technical nature of this vulnerability stems from inadequate input validation within the ELF file parsing logic. When the libdwarf library encounters an ELF file with a section group of zero size, the code path responsible for processing section group headers fails to properly validate the section size before attempting mathematical operations. This specific scenario leads to a division by zero error, which causes the application to crash and terminate unexpectedly. The flaw operates at the level of the ELF file format parsing layer, making it particularly insidious as it can be exploited through legitimate file processing operations without requiring special privileges or complex attack vectors. The SHT_GROUP section type is used to indicate section groups in ELF files, and when this section has a zero size, it creates an undefined behavior condition that the library cannot handle gracefully.
The operational impact of this vulnerability extends beyond simple service interruption, as it can affect development environments, debugging tools, and security analysis platforms that rely on libdwarf functionality. Systems using dwarfdump or similar tools for examining executable files become vulnerable to unauthenticated denial of service attacks, where an attacker can simply provide a maliciously crafted ELF file to crash these applications. This makes the vulnerability particularly concerning for automated build systems, continuous integration pipelines, and security scanning tools that process unknown or untrusted binary files. The weakness can be exploited in various contexts including software development workflows, security research, and system administration tasks where ELF file analysis is performed, potentially leading to extended downtime and operational disruption.
Organizations should implement immediate mitigation strategies by upgrading to libdwarf versions released after July 5, 2019, which contain the necessary patches to prevent the division by zero condition. Additionally, administrators should consider implementing input validation measures for any applications that process ELF files, particularly those that may encounter untrusted input from external sources. The vulnerability aligns with CWE-369, which addresses the division by zero weakness, and can be categorized under ATT&CK technique T1499.002 for network denial of service attacks. System administrators should also monitor for any applications that depend on libdwarf and ensure they are updated appropriately to prevent exploitation of this weakness in their operational environments.