CVE-2017-9520 in radare2
Summary
by MITRE
The r_config_set function in libr/config/config.c in radare2 1.5.0 allows remote attackers to cause a denial of service (use-after-free and application crash) via a crafted DEX file.
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Analysis
by VulDB Data Team • 12/08/2022
The vulnerability identified as CVE-2017-9520 resides within the radare2 reverse engineering framework version 1.5.0, specifically in the r_config_set function located in libr/config/config.c. This flaw represents a critical security issue that enables remote attackers to execute denial of service attacks through carefully crafted DEX (Dalvik Executable) files. The vulnerability manifests as a use-after-free condition that ultimately leads to application crashes, effectively rendering the software unavailable to legitimate users. The root cause stems from inadequate memory management practices within the configuration handling mechanism when processing malformed DEX file inputs.
The technical exploitation of this vulnerability occurs when radare2 attempts to parse and process a maliciously constructed DEX file through its configuration system. The r_config_set function fails to properly validate or sanitize input parameters derived from DEX file structures, leading to memory corruption issues. When the application encounters specific patterns within the DEX file headers or metadata, it attempts to access memory locations that have already been freed or reallocated, resulting in undefined behavior and subsequent application termination. This use-after-free condition falls under the common weakness enumeration CWE-416, which specifically addresses the use of memory after it has been freed, making it a well-documented and dangerous class of vulnerability.
From an operational perspective, this vulnerability presents significant risks to security researchers, penetration testers, and reverse engineers who rely on radare2 for their work. The denial of service impact means that legitimate users could be disrupted during critical analysis sessions, potentially causing loss of work or extended downtime. The remote nature of the attack vector implies that adversaries could exploit this vulnerability without requiring physical access to the target system, making it particularly dangerous in environments where radare2 is used in automated analysis pipelines or shared network resources. The vulnerability affects the core functionality of the software, undermining the reliability of the tool in professional security assessments and forensic investigations.
Mitigation strategies for CVE-2017-9520 should prioritize immediate software updates to versions that contain patched implementations of the r_config_set function. Organizations should implement network segmentation and access controls to limit exposure to potentially malicious DEX files, particularly in environments where automatic file processing occurs. Input validation measures should be enhanced to include comprehensive DEX file analysis before processing, with particular attention to header structures and metadata consistency checks. Security monitoring should be implemented to detect unusual application behavior or crash patterns that might indicate exploitation attempts. Additionally, defensive programming techniques such as implementing proper memory management practices and adding bounds checking should be considered as part of broader software hardening efforts. The vulnerability also aligns with ATT&CK technique T1499.001, which covers network denial of service attacks, and represents a clear example of how improper memory handling in security tools can create exploitable conditions for adversaries seeking to disrupt legitimate operations.