CVE-2016-10133 in MuJS
Summary
by MITRE
Heap-based buffer overflow in the js_stackoverflow function in jsrun.c in Artifex Software, Inc. MuJS allows attackers to have unspecified impact by leveraging an error when dropping extra arguments to lightweight functions.
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Analysis
by VulDB Data Team • 11/15/2022
The vulnerability identified as CVE-2016-10133 represents a critical heap-based buffer overflow within the MuJS JavaScript interpreter developed by Artifex Software Inc. This flaw exists in the js_stackoverflow function located in the jsrun.c source file, which governs how the interpreter handles stack operations during JavaScript execution. The vulnerability manifests when the interpreter encounters situations where extra arguments are passed to lightweight functions, creating an erroneous state that leads to memory corruption. The heap-based nature of this overflow indicates that the vulnerable memory allocation occurs on the heap rather than the stack, making the exploitation more complex but potentially more dangerous as it can lead to arbitrary code execution or system compromise.
The technical implementation of this vulnerability stems from inadequate bounds checking within the js_stackoverflow function when processing argument lists for lightweight JavaScript functions. When an excessive number of arguments are passed to these functions, the interpreter fails to properly validate the argument count against allocated buffer sizes, resulting in memory writes that exceed the intended buffer boundaries. This type of vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions, although the heap-based nature places it more specifically within CWE-122, heap-based buffer overflow scenarios. The flaw represents a classic case of improper input validation where the interpreter does not adequately verify argument counts against available memory allocation, creating a condition where attacker-controlled data can overwrite adjacent heap memory regions.
The operational impact of this vulnerability extends beyond simple memory corruption, as it provides attackers with potential paths to execute arbitrary code within the context of the application hosting the MuJS interpreter. When successfully exploited, the buffer overflow can lead to complete system compromise, especially when the vulnerable interpreter is used in web browsers, embedded systems, or server applications that process untrusted JavaScript input. The unspecified impact mentioned in the CVE description suggests that the consequences can vary depending on the execution environment and memory layout, but typically includes denial of service conditions, privilege escalation, or remote code execution capabilities. This vulnerability directly aligns with ATT&CK technique T1059.007, which covers JavaScript and VBScript execution, and potentially T1068, which involves exploit for privilege escalation through memory corruption attacks.
Mitigation strategies for CVE-2016-10133 require immediate patching of affected MuJS versions, as the vulnerability exists at the core interpreter level and cannot be effectively addressed through runtime configuration changes alone. Organizations should implement comprehensive monitoring for any exploitation attempts, particularly focusing on unusual argument patterns or stack operations that might indicate exploitation attempts. The fix typically involves implementing proper bounds checking within the js_stackoverflow function to ensure that argument counts never exceed allocated buffer sizes, combined with input sanitization to prevent malformed argument lists from reaching the vulnerable code path. Additionally, deployment of application whitelisting solutions and sandboxing mechanisms can help reduce the potential impact if exploitation were to occur, while regular security audits of JavaScript execution environments should be conducted to identify similar vulnerabilities in other interpreter components or third-party libraries that might be susceptible to similar buffer overflow conditions.