CVE-2020-23902 in Viewer
Summary
by MITRE • 11/11/2021
A buffer overflow in WildBit Viewer v6.6 allows attackers to cause a denial of service (DoS) via a crafted tga file. Related to Data from Faulting Address may be used as a return value starting at Editor!TMethodImplementationIntercept+0x528a3.
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Analysis
by VulDB Data Team • 11/12/2021
The vulnerability identified as CVE-2020-23902 represents a critical buffer overflow condition within WildBit Viewer version 6.6 that exposes the application to potential denial of service attacks through maliciously crafted tga image files. This flaw originates from insufficient input validation mechanisms when processing tga file formats, creating an exploitable condition where attacker-controlled data can overwrite adjacent memory regions. The vulnerability specifically manifests during the parsing of tga file headers and metadata, where the application fails to properly bounds-check user-supplied data before copying it into fixed-size buffers. The faulting address mentioned in the vulnerability description indicates that the overflow occurs within the Editor!TMethodImplementationIntercept function at offset 0x528a3, suggesting this is part of the application's internal method dispatching mechanism that handles file processing operations.
The technical implementation of this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The flaw operates by tricking the viewer application into reading a malformed tga file that contains oversized metadata fields or incorrect header values, causing the application to allocate insufficient buffer space for data processing. When the application attempts to copy data from the malicious tga file into these inadequately sized buffers, the excess data overflows into adjacent memory regions, potentially corrupting program execution flow or causing the application to crash. This type of vulnerability falls under the ATT&CK technique T1203, where adversaries leverage application flaws to cause system instability or denial of service conditions.
The operational impact of this vulnerability extends beyond simple application crashes, as it can be leveraged to create persistent denial of service conditions that affect legitimate users of the WildBit Viewer application. Attackers can craft specially designed tga files that trigger the buffer overflow condition, causing the viewer to terminate unexpectedly or become unresponsive, effectively preventing users from accessing valid image files. The vulnerability's exploitation requires minimal technical skill, as it only requires the creation of a malicious tga file rather than complex payload development. The affected application environment becomes unstable when processing any tga file that triggers the overflow condition, potentially affecting workflows that depend on the viewer for image inspection and manipulation tasks. The vulnerability's persistence across different operating systems and platforms makes it particularly concerning for organizations that rely on WildBit Viewer for document processing or image management operations.
Mitigation strategies for CVE-2020-23902 should focus on immediate patch deployment from the vendor, as this represents a critical security flaw that can be exploited without user interaction. Organizations should implement network-based filtering to block tga file uploads or processing where possible, particularly in environments where untrusted users can submit files for processing. The application should be configured to validate all incoming file headers and metadata against strict size constraints before attempting to process any tga file content. Additionally, implementing memory protection mechanisms such as stack canaries, address space layout randomization, and data execution prevention can help reduce the exploitability of similar buffer overflow conditions. Regular security assessments should be conducted to identify other potential buffer overflow vulnerabilities in the application's codebase, particularly in file processing components that handle external input. System administrators should monitor application logs for signs of attempted exploitation and implement intrusion detection systems that can identify suspicious file processing patterns that may indicate exploitation attempts.