CVE-2018-3889 in PhotoLine
Summary
by MITRE
A specially crafted PCX image processed via the application can lead to an out-of-bounds write, overwriting arbitrary data. An attacker can deliver a PCX image to trigger this vulnerability and gain code execution.
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Analysis
by VulDB Data Team • 02/28/2023
The vulnerability identified as CVE-2018-3889 represents a critical out-of-bounds write flaw within image processing functionality that affects applications handling PCX (Paintbrush) image files. This type of vulnerability falls under the category of memory corruption issues that can be exploited to achieve arbitrary code execution, making it particularly dangerous in security contexts. The flaw manifests when applications process specially crafted PCX image files that contain malformed data structures, specifically within the image header or pixel data sections.
The technical implementation of this vulnerability stems from insufficient bounds checking during the parsing of PCX image format specifications. When an application attempts to decode a PCX file, it typically reads header information to determine image dimensions, color depth, and other metadata before proceeding with pixel data processing. In the case of CVE-2018-3889, the malicious PCX file contains crafted values that cause the application to allocate memory buffers based on incorrect dimensions or offsets. This misalignment results in the application writing data beyond the allocated memory boundaries, effectively overwriting adjacent memory regions that may contain critical program data, function pointers, or return addresses.
The operational impact of this vulnerability extends beyond simple memory corruption, as it provides attackers with a pathway to achieve remote code execution within the context of the vulnerable application. This exploitation vector aligns with ATT&CK technique T1203 - Exploitation for Client Execution, where adversaries leverage application vulnerabilities to execute malicious code. The out-of-bounds write can be manipulated to overwrite critical memory locations such as stack canaries, return addresses, or function pointers, enabling attackers to redirect program execution flow and inject malicious payloads. This vulnerability particularly affects applications that process untrusted image files without proper input validation, including image viewers, document processors, and web applications handling image uploads.
Security professionals should note that this vulnerability demonstrates the importance of proper input validation and bounds checking in multimedia processing libraries. The flaw represents a classic example of CWE-787 - Out-of-bounds Write, which occurs when a program writes data past the end or before the beginning of a fixed-length buffer. Applications processing image formats should implement robust validation mechanisms that verify all header fields and ensure that calculated buffer sizes match actual data requirements. The vulnerability also highlights the necessity of using modern programming practices such as buffer overflow protection mechanisms, address space layout randomization, and stack canaries to mitigate exploitation success rates even when such flaws exist in the codebase.
Mitigation strategies for CVE-2018-3889 should focus on immediate patching of affected applications, implementing strict input validation for all image file formats, and deploying network-based intrusion detection systems to monitor for suspicious PCX file transfers. Organizations should also consider implementing sandboxing techniques for image processing operations and establishing secure coding practices that emphasize bounds checking and memory safety in multimedia handling components. The vulnerability serves as a reminder that image processing libraries require rigorous security testing and validation, particularly when handling potentially malicious input from untrusted sources, as these components often run with elevated privileges and can provide direct access to system resources.