CVE-2021-46497 in Jsish
Summary
by MITRE • 01/28/2022
Jsish v3.5.0 was discovered to contain a heap-use-after-free via jsi_UserObjDelete in src/jsiUserObj.c. This vulnerability can lead to a Denial of Service (DoS).
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Analysis
by VulDB Data Team • 01/30/2022
The heap-use-after-free vulnerability identified in Jsish v3.5.0 represents a critical memory safety issue that can be exploited to disrupt application functionality and potentially enable further attack vectors. This vulnerability resides within the jsi_UserObjDelete function located in the src/jsiUserObj.c source file, indicating a memory management flaw that occurs during object deletion operations within the JavaScript interpreter. The flaw manifests when the system attempts to free memory that has already been released, creating a scenario where subsequent access to that memory location can result in unpredictable behavior.
The technical exploitation of this heap-use-after-free vulnerability occurs when the jsish interpreter processes user objects that are scheduled for deletion, leading to a situation where memory is freed but not properly invalidated. This creates a window where the application may attempt to access previously freed memory locations, resulting in undefined behavior that typically manifests as application crashes or denial of service conditions. The vulnerability specifically targets the user object deletion mechanism, suggesting that improper memory management during cleanup operations can lead to memory corruption that affects the entire interpreter's stability.
From an operational perspective, this vulnerability presents a significant risk to systems relying on Jsish for JavaScript execution, particularly in environments where the interpreter handles untrusted input or user-generated code. The denial of service impact means that adversaries can potentially crash the application or render it unresponsive through carefully crafted input that triggers the memory corruption during object deletion. This vulnerability falls under CWE-416, which specifically addresses use-after-free conditions, and aligns with ATT&CK technique T1499.004 for endpoint denial of service, making it a serious concern for system availability and reliability.
The remediation approach for this vulnerability requires immediate patching of the Jsish interpreter to version v3.5.1 or later, which contains the necessary memory management fixes to prevent the use-after-free condition. Additionally, system administrators should implement input validation and sanitization measures to limit the potential impact of malicious input that could trigger the vulnerability. Organizations should also consider implementing runtime monitoring and intrusion detection systems to identify potential exploitation attempts, as the heap-use-after-free condition can sometimes be leveraged for more sophisticated attacks if combined with other vulnerabilities. The fix typically involves proper memory management practices including ensuring that pointers are set to NULL after memory deallocation and implementing proper reference counting mechanisms to prevent premature object deletion.