CVE-2016-10210 in YARA
Summary
by MITRE
libyara/lexer.l in YARA 3.5.0 allows remote attackers to cause a denial of service (NULL pointer dereference and application crash) via a crafted rule that is mishandled in the yy_get_next_buffer function.
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Analysis
by VulDB Data Team • 11/24/2022
The vulnerability identified as CVE-2016-10210 resides within the YARA threat hunting and malware analysis framework version 3.5.0, specifically within the libyara library's lexer component. This issue manifests in the lexer.l file which is responsible for tokenizing rule definitions during the parsing process. The flaw represents a classic null pointer dereference vulnerability that can be exploited remotely through maliciously crafted YARA rules, making it particularly dangerous in environments where YARA rules are processed from untrusted sources.
The technical execution of this vulnerability occurs within the yy_get_next_buffer function, which is part of the lexical analysis phase of YARA's rule processing pipeline. When a specially crafted rule is presented to the system, the lexer fails to properly validate input data structures, leading to a scenario where a null pointer is dereferenced during buffer management operations. This improper handling of buffer states during lexical analysis causes the application to crash immediately, resulting in a denial of service condition that affects the entire YARA processing capability.
From an operational perspective, this vulnerability presents significant risks to security operations teams and organizations that rely on YARA for malware detection and threat hunting activities. The remote exploitation capability means that an attacker could potentially disrupt security operations by crashing YARA-based systems without requiring local access or elevated privileges. This makes the vulnerability particularly attractive to threat actors seeking to evade detection or disrupt security infrastructure, as it can be triggered simply by submitting malicious rules to any system running YARA 3.5.0.
The vulnerability aligns with CWE-476 which identifies null pointer dereference as a critical weakness in software systems, and it maps to ATT&CK technique T1566 which covers social engineering tactics involving the delivery of malicious payloads. Organizations using YARA for security automation and monitoring may experience service interruptions during critical threat hunting operations, potentially allowing malicious actors to operate undetected while the system is temporarily unavailable.
Mitigation strategies should prioritize immediate patching of YARA to versions 3.6.0 or later where this vulnerability has been addressed through proper null pointer validation in the lexer component. Additionally, organizations should implement strict rule validation processes for any YARA rules sourced from external or untrusted repositories, employing sandboxing techniques to isolate rule processing operations. Network segmentation and access controls should be implemented to limit exposure of YARA processing systems to untrusted inputs, while regular security assessments should verify that rule validation mechanisms are functioning correctly. System monitoring should be enhanced to detect application crashes and restart processes automatically to maintain service availability during potential exploitation attempts.