CVE-2017-7975 in jbig2dec
Summary
by MITRE
Artifex jbig2dec 0.13, as used in Ghostscript, allows out-of-bounds writes because of an integer overflow in the jbig2_build_huffman_table function in jbig2_huffman.c during operations on a crafted JBIG2 file, leading to a denial of service (application crash) or possibly execution of arbitrary code.
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Analysis
by VulDB Data Team • 12/01/2022
The vulnerability CVE-2017-7975 represents a critical security flaw in the jbig2dec library version 0.13, which is utilized by the Ghostscript document processing system. This issue manifests as an integer overflow within the jbig2_build_huffman_table function located in the jbig2_huffman.c source file, creating a condition where maliciously crafted JBIG2 image files can trigger memory corruption during normal document processing operations. The vulnerability affects systems that handle JBIG2 encoded images, particularly those using Ghostscript as a document rendering engine, making it a significant concern for organizations that process scanned documents, fax images, or any content containing JBIG2 encoded data.
The technical exploitation of this vulnerability occurs through an integer overflow condition that leads to out-of-bounds memory writes during Huffman table construction. When the jbig2_build_huffman_table function processes malformed JBIG2 data, an integer overflow causes the calculation of array indices to wrap around to extremely small or negative values, resulting in memory corruption. This flaw specifically impacts the jbig2dec library's handling of Huffman coding tables used in JBIG2 image compression, where the library attempts to allocate memory based on incorrect calculations derived from malicious input data. The vulnerability is classified under CWE-190 as an integer overflow condition, representing a fundamental flaw in input validation and memory management within the library's parsing logic.
The operational impact of CVE-2017-7975 extends beyond simple denial of service to potentially enable remote code execution in vulnerable environments. When exploited, this vulnerability can cause application crashes that result in service disruption, while in more sophisticated attack scenarios, the memory corruption could be leveraged to execute arbitrary code with the privileges of the affected application. This makes the vulnerability particularly dangerous for web applications, document processing services, and email servers that automatically process JBIG2 encoded content. The attack surface is broad as any system that utilizes Ghostscript or jbig2dec for document handling could be affected, including enterprise document management systems, fax servers, and online document conversion services.
Organizations should implement immediate mitigations including updating to patched versions of Ghostscript and jbig2dec libraries, as the vulnerability was addressed in subsequent releases. System administrators should also consider implementing input validation measures to filter or reject JBIG2 content from untrusted sources, particularly in environments where automatic document processing occurs. Network segmentation and access controls should be enhanced to limit exposure of systems that process document content, while monitoring systems should be configured to detect anomalous processing patterns that might indicate exploitation attempts. Additionally, security teams should conduct vulnerability assessments to identify all systems utilizing affected libraries and ensure proper patch management procedures are in place to prevent future exploitation of similar integer overflow vulnerabilities. The ATT&CK framework categorizes this vulnerability under the T1203 technique for Exploitation for Defense Evasion, as attackers could potentially use such flaws to establish persistent access through compromised document processing systems.