CVE-2018-10199 in mruby
Summary
by MITRE
In versions of mruby up to and including 1.4.0, a use-after-free vulnerability exists in src/io.c::File#initilialize_copy(). An attacker that can cause Ruby code to be run can possibly use this to execute arbitrary code.
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Analysis
by VulDB Data Team • 02/28/2023
The vulnerability identified as CVE-2018-10199 represents a critical use-after-free condition within the mruby implementation that affects versions up to and including 1.4.0. This flaw manifests in the File#initialize_copy method within the src/io.c source file, creating a scenario where memory that has been freed is subsequently accessed, potentially leading to arbitrary code execution. The vulnerability stems from improper memory management practices during object copying operations, particularly when handling file objects in the mruby runtime environment.
This security flaw operates at the intersection of memory safety and application sandboxing, where an attacker with the ability to execute Ruby code within the mruby environment can exploit the use-after-free condition to gain unauthorized control over the system. The vulnerability is classified under CWE-416 as a Use After Free condition, which occurs when a program continues to reference memory after it has been freed, creating opportunities for memory corruption and code execution. The attack vector requires the attacker to have code execution privileges within the mruby context, making this a privilege escalation vulnerability that can be leveraged for remote code execution in vulnerable applications.
The operational impact of this vulnerability extends beyond simple memory corruption, as it provides attackers with a potential pathway for arbitrary code execution that could be exploited in web applications, embedded systems, or any environment where mruby is used as a scripting engine. The flaw is particularly concerning because it allows for potential exploitation of the underlying system, enabling attackers to execute malicious payloads, escalate privileges, or perform other harmful actions. The vulnerability affects not only the immediate execution environment but also the broader security posture of systems relying on mruby for scripting capabilities.
Mitigation strategies for CVE-2018-10199 involve immediate patching of affected mruby installations to versions that address the memory management issue in the File#initialize_copy method. Organizations should implement comprehensive monitoring for unauthorized code execution attempts and maintain up-to-date security patches for all mruby-dependent applications. The fix typically involves proper memory handling in the file copying operations to ensure that references are not maintained after memory deallocation. Additionally, implementing runtime protections such as address space layout randomization and stack canaries can provide defense-in-depth measures against exploitation attempts. Security teams should also consider implementing application whitelisting and sandboxing mechanisms to limit the potential impact of successful exploitation attempts, aligning with ATT&CK tactics that focus on privilege escalation and execution.