CVE-2022-1106 in mruby
Summary
by MITRE • 03/27/2022
use after free in mrb_vm_exec in GitHub repository mruby/mruby prior to 3.2.
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Analysis
by VulDB Data Team • 03/31/2022
The vulnerability identified as CVE-2022-1106 represents a critical use-after-free condition within the mruby interpreter implementation, specifically within the mrb_vm_exec function. This flaw exists in mruby versions prior to 3.2 and constitutes a fundamental memory safety issue that can be exploited to execute arbitrary code or cause application crashes. The vulnerability stems from improper memory management during virtual machine execution, where freed memory regions are accessed after being deallocated, creating opportunities for malicious code injection and system compromise.
This use-after-free vulnerability falls under the CWE-416 category, which specifically addresses the use of freed memory condition. The flaw occurs when the mruby virtual machine executes code that triggers the mrb_vm_exec function to access memory that has already been freed during previous operations. The vulnerability is particularly dangerous because mruby is designed as a lightweight scripting engine often embedded within applications, making it a prime target for exploitation in various software environments. The exploitation of this vulnerability can result in remote code execution, denial of service, or information disclosure depending on the specific implementation context.
The operational impact of CVE-2022-1106 extends beyond simple application instability, as it can enable attackers to gain unauthorized system access through carefully crafted malicious scripts. When exploited, the vulnerability allows attackers to manipulate memory contents and potentially execute arbitrary code with the privileges of the affected application. This makes the vulnerability particularly concerning for applications that process untrusted input through the mruby interpreter, as it can serve as a gateway for more extensive attacks. The vulnerability's presence in the virtual machine execution engine means that any application relying on mruby for scripting capabilities is potentially at risk, especially those in web applications, embedded systems, or networked services.
Mitigation strategies for CVE-2022-1106 primarily involve upgrading to mruby version 3.2 or later, which contains the necessary patches to address the memory management issues. Organizations should conduct thorough vulnerability assessments to identify all systems using affected versions of mruby and prioritize their remediation. Additional protective measures include implementing strict input validation for any mruby scripts, employing sandboxing techniques to limit potential damage from exploitation, and monitoring for anomalous behavior that might indicate successful exploitation attempts. The vulnerability also highlights the importance of regular security updates and maintaining current versions of interpreted languages and scripting engines, as these components often serve as attack vectors in modern software environments. From an ATT&CK perspective, this vulnerability maps to techniques involving code injection and privilege escalation, making it a significant concern for defensive security teams.