CVE-2019-7148 in elfutils
Summary
by MITRE
An attempted excessive memory allocation was discovered in the function read_long_names in elf_begin.c in libelf in elfutils 0.174. Remote attackers could leverage this vulnerability to cause a denial-of-service via crafted elf input, which leads to an out-of-memory exception.
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Analysis
by VulDB Data Team • 05/06/2020
The vulnerability identified as CVE-2019-7148 represents a critical memory allocation flaw within the elfutils library ecosystem, specifically affecting the read_long_names function in elf_begin.c. This issue manifests as an excessive memory allocation attempt that occurs when processing crafted elf input files, creating a significant risk for systems relying on libelf for elf file analysis and manipulation. The vulnerability resides in the fundamental handling of elf file structures and demonstrates how seemingly benign file parsing operations can be exploited to consume excessive system resources.
The technical implementation of this vulnerability stems from inadequate input validation and memory management within the elfutils library's parsing logic. When the read_long_names function processes malformed elf files containing specially crafted long name entries, it fails to properly constrain memory allocation requests based on the input data. This allows attackers to construct elf files that trigger disproportionate memory consumption during the parsing process, ultimately leading to out-of-memory conditions that can crash applications or services utilizing libelf. The flaw operates at the intersection of buffer management and resource allocation, where the expected memory requirements for processing elf file metadata are not properly bounded by input validation mechanisms.
From an operational perspective, this vulnerability creates substantial denial-of-service risks for systems that process elf files from untrusted sources, including but not limited to software deployment systems, security scanning tools, and system monitoring applications. The impact extends beyond simple service disruption as the vulnerability can be exploited remotely through any application that utilizes libelf for elf file processing, making it particularly dangerous in networked environments. The out-of-memory exceptions generated by this flaw can cause cascading failures in applications that do not properly handle memory allocation failures, potentially leading to system instability or complete service unavailability.
The vulnerability aligns with CWE-770, which addresses allocation of resources without limits or with inadequate limits, and represents a classic example of resource exhaustion attacks that can be categorized under the ATT&CK technique T1499.1 for Network Denial of Service. Organizations using affected versions of elfutils should implement immediate mitigations including input validation for elf files, deployment of updated library versions, and application-level memory constraints to prevent exploitation. Additionally, network segmentation and access controls should be implemented to limit exposure of systems that process elf files from untrusted sources, as the vulnerability can be leveraged remotely without requiring authentication or elevated privileges. The remediation strategy should focus on updating to patched versions of elfutils while implementing defensive programming practices to prevent similar issues in custom elf processing implementations.