CVE-2009-2175 in xcftools
Summary
by MITRE
Stack-based buffer overflow in the flattenIncrementally function in flatten.c in xcftools 1.0.4, as reachable from the (1) xcf2pnm and (2) xcf2png utilities, allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a crafted image that causes a conversion to a location "above or to the left of the canvas." NOTE: some of these details are obtained from third party information.
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Analysis
by VulDB Data Team • 08/11/2021
The vulnerability identified as CVE-2009-2175 represents a critical stack-based buffer overflow in the xcftools 1.0.4 library, specifically within the flattenIncrementally function located in flatten.c. This flaw affects two primary utilities: xcf2pnm and xcf2png, which are used for converting GIMP XCF image files to other formats. The vulnerability arises when these tools process specially crafted XCF images that contain conversion instructions directing the image data to locations positioned "above or to the left of the canvas," creating an exploitable condition that can be leveraged by remote attackers.
The technical implementation of this vulnerability stems from inadequate bounds checking within the flattenIncrementally function, which fails to validate the coordinates and dimensions of image data during the conversion process. When the conversion utilities encounter image data that specifies positions outside the normal canvas boundaries, the function attempts to write data to memory locations that are not properly allocated for the operation. This results in a stack buffer overflow that can corrupt adjacent memory regions, potentially leading to arbitrary code execution or system crashes. The flaw is classified as a stack-based buffer overflow under CWE-121, which specifically addresses the condition where data written to a stack buffer exceeds the buffer's allocated size, causing memory corruption.
The operational impact of this vulnerability extends beyond simple denial of service, as it presents a potential pathway for remote code execution. Attackers can craft malicious XCF image files that, when processed by vulnerable systems, will trigger the buffer overflow condition. This allows for arbitrary code execution with the privileges of the user running the affected utilities, potentially enabling attackers to gain unauthorized access to systems or escalate privileges. The vulnerability affects systems that process XCF images through the xcf2pnm and xcf2png tools, making it particularly dangerous in environments where image conversion utilities are frequently used or exposed to untrusted input sources. According to ATT&CK framework, this vulnerability maps to T1203 (Exploitation for Client Execution) and T1059 (Command and Scripting Interpreter) as attackers can leverage the overflow to execute malicious code.
Mitigation strategies for CVE-2009-2175 should focus on immediate patching of the xcftools library to version 1.0.5 or later, which contains the necessary fixes for the buffer overflow condition. System administrators should implement input validation measures to prevent processing of untrusted XCF files, particularly in web-facing applications or environments where users can upload images. Additionally, deploying application whitelisting solutions and restricting execution privileges of the affected utilities can help reduce the attack surface. Network segmentation and monitoring for suspicious file conversion activities can provide early detection of potential exploitation attempts, while regular security assessments should verify that no systems remain vulnerable to this and similar buffer overflow conditions that could be exploited for privilege escalation or persistent access.