CVE-2017-9216 in jbig2dec
Summary
by MITRE
libjbig2dec.a in Artifex jbig2dec 0.13, as used in MuPDF and Ghostscript, has a NULL pointer dereference in the jbig2_huffman_get function in jbig2_huffman.c. For example, the jbig2dec utility will crash (segmentation fault) when parsing an invalid file.
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Analysis
by VulDB Data Team • 09/11/2024
The vulnerability identified as CVE-2017-9216 represents a critical null pointer dereference flaw within the jbig2dec library version 0.13, which is widely integrated into document processing systems including MuPDF and Ghostscript. This issue stems from insufficient input validation mechanisms within the jbig2_huffman_get function located in the jbig2_huffman.c source file, creating a scenario where maliciously crafted jbig2 encoded files can trigger system instability. The flaw manifests when the library attempts to process malformed input data that lacks proper Huffman table structure validation, leading to an attempt to dereference a null pointer during the decoding process.
The technical implementation of this vulnerability operates at the intersection of memory management and input parsing within the jbig2 decoding framework. When the jbig2_huffman_get function encounters an invalid Huffman table structure within a jbig2 file, it fails to properly validate the pointer references before attempting to access them. This particular flaw aligns with CWE-476 which specifically addresses NULL pointer dereference conditions in software implementations. The function's failure to establish proper bounds checking or pointer validation creates an exploitable condition where a segmentation fault occurs, effectively crashing the application that is processing the malformed file.
The operational impact of CVE-2017-9216 extends beyond simple application crashes to represent a potential denial of service vector that can be exploited by adversaries seeking to disrupt document processing workflows. Systems utilizing MuPDF or Ghostscript for document rendering, conversion, or archival processes become vulnerable to this attack when processing untrusted jbig2 encoded content. The vulnerability is particularly concerning in environments where automated document processing occurs, as a single malicious file could cause cascading failures across multiple applications or services that depend on these libraries. This scenario directly maps to ATT&CK technique T1499.004 which covers network denial of service attacks through resource exhaustion or application crashes.
Mitigation strategies for this vulnerability require immediate patching of affected systems to update to jbig2dec versions that address the null pointer dereference condition. System administrators should prioritize updating both MuPDF and Ghostscript installations to versions that include fixed implementations of the jbig2dec library. Additional protective measures include implementing strict file validation procedures that verify jbig2 file integrity before processing, deploying sandboxed environments for document analysis, and establishing automated monitoring systems to detect unusual application crash patterns. Organizations should also consider implementing input sanitization layers that can identify and reject malformed jbig2 content before it reaches the vulnerable library components. The remediation approach aligns with defensive cybersecurity practices outlined in NIST SP 800-34 and ISO 27001 frameworks for vulnerability management and system hardening.