CVE-2022-23319 in pcf2bdf
Summary
by MITRE • 02/17/2022
A segmentation fault during PCF file parsing in pcf2bdf versions >=1.05 allows an attacker to trigger a program crash via a specially crafted PCF font file. This crash affects the availability of the software and dependent downstream components.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 02/19/2022
The vulnerability identified as CVE-2022-23319 represents a critical segmentation fault within the pcf2bdf utility, specifically during the parsing of PCF font files. This flaw exists in versions 1.05 and later of the software, where the application fails to properly validate input data when processing PCF font format files. The segmentation fault occurs due to improper memory handling during the parsing routine, causing the program to terminate abruptly and potentially leading to a denial of service condition. The PCF (Portable Compiled Format) is a widely used font format in X Window System environments, making this vulnerability particularly concerning for systems that rely on font conversion utilities for display management. The flaw stems from inadequate bounds checking and memory allocation validation within the parsing logic, allowing maliciously crafted input to cause unexpected program termination.
The technical implementation of this vulnerability demonstrates a classic buffer over-read condition that falls under CWE-125, where the application attempts to access memory beyond the allocated buffer boundaries. When pcf2bdf encounters malformed PCF data structures, the parser fails to properly validate the size fields or header information, leading to an attempt to read beyond the intended memory limits. This results in a segmentation fault that terminates the process and prevents normal operation. The vulnerability operates at the application level within the font processing pipeline, where PCF files are converted to BDF (Bitmap Distribution Format) for compatibility with other systems. The flaw affects the software's ability to handle malformed input gracefully, instead causing an abrupt crash that can be exploited to disrupt service availability.
The operational impact of CVE-2022-23319 extends beyond simple program termination to potentially affect broader system availability and stability. In environments where pcf2bdf is used as part of automated font processing workflows or integrated into larger software systems, this vulnerability can lead to cascading failures that impact dependent applications. The denial of service condition can be particularly problematic in server environments or embedded systems where font conversion is a routine operation. Attackers can exploit this vulnerability by creating specially crafted PCF files that trigger the segmentation fault, effectively rendering the utility unusable until manually restarted or patched. This vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through exploitation of software vulnerabilities, and can be leveraged in broader attack chains targeting system availability.
Mitigation strategies for CVE-2022-23319 should focus on immediate patching of affected software versions, with particular attention to the specific memory handling routines within the pcf2bdf utility. System administrators should implement input validation measures that filter or sanitize PCF files before processing, particularly in environments where untrusted font data might be encountered. The vulnerability can be addressed through proper bounds checking, input validation, and robust error handling mechanisms that prevent memory access violations. Organizations should also consider implementing monitoring solutions to detect unusual program termination patterns that might indicate exploitation attempts. Additionally, the use of sandboxing techniques or restricted execution environments for font processing utilities can limit the impact of potential exploitation attempts. Regular security assessments of font processing pipelines and input validation routines should be conducted to prevent similar vulnerabilities from emerging in other components of the system.