CVE-2017-9906 in XnView Classic
Summary
by MITRE
XnView Classic for Windows Version 2.40 allows remote attackers to cause a denial of service or possibly have unspecified other impact via a crafted .fpx file, related to "Data from Faulting Address is used as one or more arguments in a subsequent Function Call starting at Xfpx!gffGetFormatInfo+0x0000000000028508."
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 10/23/2019
The vulnerability identified as CVE-2017-9906 affects XnView Classic for Windows version 2.40 and represents a critical denial of service condition that can be exploited through maliciously crafted .fpx files. This file format vulnerability stems from improper handling of malformed data structures within the Xfpx module, specifically at the gffGetFormatInfo function where faulting address data is utilized as arguments in subsequent function calls. The flaw manifests when the application processes specially constructed floating point extension files that contain malformed metadata or corrupted binary structures.
The technical root cause of this vulnerability lies in the insufficient input validation and error handling mechanisms within the XnView image processing pipeline. When the application encounters a crafted .fpx file, the parsing routine fails to properly validate the data integrity of the file's header or embedded metadata structures. This leads to a scenario where memory addresses containing corrupted data are dereferenced and passed as parameters to subsequent function calls, creating a cascade of potential system instability. The vulnerability operates at the intersection of buffer over-read conditions and improper pointer management, with the faulting address being directly utilized without adequate bounds checking or sanitization.
From an operational perspective, this vulnerability presents significant risks to organizations relying on XnView Classic for image processing tasks. Remote attackers can exploit this flaw to disrupt services by causing application crashes or system hangs, effectively creating a denial of service condition that impacts legitimate users. The potential for unspecified additional impacts suggests that this vulnerability might also provide opportunities for privilege escalation or information disclosure, though the exact scope remains unclear. The attack vector requires minimal user interaction since the vulnerability can be triggered through automated file processing, making it particularly dangerous in environments where batch processing or automated image handling is common.
The vulnerability aligns with CWE-125 Out-of-bounds Read and CWE-787 Out-of-bounds Write categories, representing a classic case of memory corruption through improper input validation. It also maps to ATT&CK technique T1203 Exploitation for Client Execution, where adversaries leverage application vulnerabilities to execute malicious code or cause system instability. Organizations should consider this vulnerability as part of broader application security assessments, particularly in environments where legacy image processing applications are still in use. The impact extends beyond simple service disruption to potentially compromise the integrity of image processing workflows and data handling pipelines.
Mitigation strategies should prioritize immediate patching of affected XnView Classic installations to version 2.41 or later, which contains the necessary fixes for this vulnerability. System administrators should also implement file validation measures, including content type verification and sandboxed processing environments for image files. Network-level controls such as file type filtering and application whitelisting can provide additional defense-in-depth layers. Organizations should conduct thorough vulnerability assessments to identify all instances of XnView Classic deployments and ensure comprehensive patch management processes are in place to prevent similar vulnerabilities from remaining unaddressed. Regular security updates and application lifecycle management practices should be enforced to minimize exposure to such memory corruption vulnerabilities.