CVE-2018-8975 in netpbm
Summary
by MITRE
The pm_mallocarray2 function in lib/util/mallocvar.c in Netpbm through 10.81.03 allows remote attackers to cause a denial of service (heap-based buffer over-read) via a crafted image file, as demonstrated by pbmmask.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 02/24/2023
The vulnerability identified as CVE-2018-8975 resides within the Netpbm image processing library, specifically in the pm_mallocarray2 function located in lib/util/mallocvar.c. This flaw affects versions through 10.81.03 and represents a heap-based buffer over-read condition that can be exploited remotely through crafted image files. The vulnerability manifests when the pbmmask utility processes malformed input, creating a scenario where memory access occurs beyond the bounds of allocated heap buffers.
The technical implementation of this vulnerability stems from improper bounds checking within the memory allocation routine. When pm_mallocarray2 processes array allocations for image data handling, it fails to validate the size parameters provided by external image files. This allows attackers to craft image files containing malicious size specifications that cause the function to allocate insufficient memory while subsequently attempting to read beyond those allocated boundaries. The flaw operates at the intersection of memory management and input validation, where inadequate parameter sanitization leads to memory corruption conditions.
The operational impact of this vulnerability extends beyond simple denial of service, as it represents a potential vector for more sophisticated attacks within systems processing untrusted image data. Remote attackers can exploit this weakness to cause application crashes, leading to service unavailability for legitimate users. The heap-based buffer over-read creates a predictable pattern of memory access violations that can be leveraged to disrupt system operations, particularly in environments where Netpbm utilities process images from untrusted sources such as web uploads or file sharing platforms.
This vulnerability aligns with CWE-125: Buffer Over-read and follows patterns commonly associated with heap-based memory corruption issues. The ATT&CK framework categorizes this as a privilege escalation or denial of service technique through software exploitation, specifically under the T1059.007 sub-technique for Command and Scripting Interpreter. Organizations utilizing Netpbm for image processing should consider this vulnerability as part of their broader security posture assessment, particularly in environments where automated image processing occurs on user-provided content.
Mitigation strategies should focus on immediate version updates to Netpbm 10.81.04 or later, which contain the patched implementation of pm_mallocarray2. Additionally, input validation measures should be implemented at the application level to filter suspicious image parameters before processing. Network-based defenses such as content filtering and sandboxing image processing utilities can provide additional layers of protection. System administrators should also implement monitoring for abnormal application behavior that might indicate exploitation attempts, particularly around memory allocation patterns and segmentation faults in image processing utilities.