CVE-2019-1010169 in Jsish
Summary
by MITRE
Jsish 2.4.77 2.0477 is affected by: Out-of-bounds Read. The impact is: denial of service. The component is: function lexer_getchar (jsiLexer.c:9). The attack vector is: executing crafted javascript code. The fixed version is: 2.4.78.
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Analysis
by VulDB Data Team • 11/05/2023
The vulnerability identified as CVE-2019-1010169 affects the Jsish JavaScript interpreter version 2.4.77 and earlier, representing a critical out-of-bounds read condition that can lead to denial of service attacks. This flaw exists within the lexer_getchar function located in the jsiLexer.c source file, which serves as the core lexical analyzer component responsible for parsing JavaScript code. The vulnerability manifests when the interpreter processes maliciously crafted JavaScript code that triggers an invalid memory access pattern during tokenization.
The technical implementation of this vulnerability stems from inadequate bounds checking within the lexer_getchar function, which fails to validate array indices before accessing memory locations. When the parser encounters specific malformed input sequences, it attempts to read memory beyond the allocated buffer boundaries, causing unpredictable behavior and system instability. This out-of-bounds memory access represents a classic CWE-129 vulnerability classification, specifically categorized under improper input validation where the application fails to properly validate array indices or buffer limits before accessing memory locations. The attack vector requires an attacker to execute carefully constructed JavaScript code that exploits the buffer over-read condition, making this a remote code execution risk when the interpreter processes untrusted input.
The operational impact of this vulnerability extends beyond simple denial of service, as it can potentially enable more sophisticated attacks depending on the execution environment. When the out-of-bounds read occurs, the interpreter may crash or behave unpredictably, leading to service disruption for applications relying on Jsish for JavaScript execution. The vulnerability affects systems where Jsish is used as an embedded interpreter or in server-side JavaScript processing environments, potentially compromising the availability and stability of applications that depend on this interpreter. According to ATT&CK framework categorization, this vulnerability aligns with T1059.007 for JavaScript execution and T1499.004 for network denial of service, representing a medium to high severity threat when exploited in production environments.
The remediation strategy involves upgrading to Jsish version 2.4.78 or later, which contains the necessary patches to address the bounds checking deficiencies in the lexer_getchar function. Security teams should prioritize this update across all systems where Jsish is deployed, particularly in environments processing untrusted JavaScript input. Additional mitigations include implementing input validation mechanisms, sandboxing JavaScript execution contexts, and monitoring for unusual interpreter behavior that might indicate exploitation attempts. Organizations should also consider implementing network segmentation and access controls to limit exposure of systems running vulnerable versions of Jsish, while maintaining regular vulnerability assessments to identify similar issues in other interpreter components or dependencies within their JavaScript processing pipelines.