CVE-2017-15600 in Libextractor
Summary
by MITRE
In GNU Libextractor 1.4, there is a NULL Pointer Dereference in the EXTRACTOR_nsf_extract_method function of plugins/nsf_extractor.c.
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Analysis
by VulDB Data Team • 01/04/2023
The vulnerability identified as CVE-2017-15600 represents a critical null pointer dereference flaw within GNU Libextractor version 1.4, specifically within the EXTRACTOR_nsf_extract_method function located in plugins/nsf_extractor.c. This issue arises during the processing of NSF (Notes Storage Facility) files, which are proprietary file formats used by IBM Domino server for storing email and other data. The flaw occurs when the software attempts to dereference a null pointer while handling malformed or specially crafted NSF files, potentially leading to application crashes or unexpected behavior.
The technical implementation of this vulnerability stems from inadequate input validation and error handling within the NSF file processing module. When the EXTRACTOR_nsf_extract_method function encounters certain malformed NSF file structures, it fails to properly check for null pointer conditions before attempting to access memory locations. This null pointer dereference creates a condition where the application attempts to execute operations on a memory address that has not been properly initialized or allocated, resulting in a segmentation fault or application termination. The vulnerability is classified as a CWE-476 Null Pointer Dereference, which is a well-documented weakness in software security that can lead to denial of service conditions and potentially more severe exploitation scenarios.
The operational impact of this vulnerability extends beyond simple application crashes, as it can be leveraged by attackers to disrupt services or potentially escalate privileges in systems that rely on GNU Libextractor for file content analysis. When exploited, this vulnerability can cause denial of service conditions affecting applications that utilize the library for metadata extraction from NSF files, particularly in environments where automated file processing is common. The flaw is particularly concerning in enterprise environments where IBM Domino servers are prevalent and automated content extraction processes are implemented, as it could be triggered through malicious file uploads or file processing workflows.
Mitigation strategies for CVE-2017-15600 should prioritize immediate patching of GNU Libextractor to version 1.5 or later, which contains the necessary fixes for the null pointer dereference issue. Organizations should also implement input validation measures that prevent malformed NSF files from being processed by systems utilizing the library. Additionally, network segmentation and access controls should be enforced to limit exposure of systems that process NSF files, reducing the attack surface. The vulnerability aligns with ATT&CK technique T1203, which covers Exploitation for Client Execution, as it can be exploited through manipulation of file inputs that are processed by vulnerable applications. Security monitoring should include detection of abnormal application termination patterns and memory access violations that could indicate exploitation attempts, while also implementing proper error handling and graceful degradation mechanisms in file processing workflows.