CVE-2023-25433: Buffer Overflow Vulnerability in libtiff 4.5. via tiffcrop tool Cause Heap-Buffer-Overflow and SEGV

CVE-2023-25433 is a vulnerability that has been recently discovered in the libtiff library, specifically in version 4.5.. This critical vulnerability could lead to buffer overflow (heap-buffer-overflow) and segmentation fault (SEGV) when processing TIFF files with the tiffcrop tool due to incorrect updating of the buffer size post the rotateImage() function execution in tiffcrop.c file.

This post aims to provide a clear explanation of the vulnerability, the code snippet involved, exploit details, and original references for CVE-2023-25433. Please remember that understanding vulnerabilities helps in their mitigation and assists in developing safe and secure software.

Code snippet

The issue can be traced back to the source code of libtiff, particularly in the tiffcrop.c file located at the "/libtiff/tools/tiffcrop.c" with the snippet presenting the problem at line number 8499. The following is the code snippet related to this vulnerability:

static int rotateImage(TIFFRGBAImage* img, uint32* raster, uint32* rastero, tsample_t sample, ImageOrientation orientation) {
// ...[snip]...
memcpy(rastero, raster, img->width * img->height * 4);
// Here occurs the incorrect buffer size updating
img->width = dstwidth;
img->height = dstheight;
}

Vulnerability explanation

The vulnerability arises when the tool processes the TIFF file, resulting in an incorrect update of buffer size after the execution of the rotateImage() function. As a consequence, the memcpy function causes the buffer to overflow, potentially leading to heap-buffer-overflow and segmentation fault (SEGV) issues.

Exploit details

An attacker can exploit this vulnerability by crafting a malicious TIFF file and using it as input for the tiffcrop tool. If successfully exploited, an attacker can potentially execute arbitrary code in the system or cause a crash leading to denial of service (DoS).

Original references

1. https://gitlab.com/libtiff/libtiff/ - Official libtiff repository containing the vulnerable code.
2. https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-25433 - MITRE CVE page for CVE-2023-25433.

Conclusion

CVE-2023-25433 is a critical buffer overflow vulnerability in version 4.5. of the libtiff library, specifically in the tiffcrop.c file, which may cause heap-buffer-overflow and SEGV due to incorrect updating of buffer size following the rotateImage() function. When exploiting, an attacker can execute arbitrary code or crash systems leading to denial of service (DoS). We hope this detailed explanation will assist developers in understanding the issue and finding the best practices to avoid similar vulnerabilities in their software.

Timeline

Published on: 06/29/2023 20:15:00 UTC
Last modified on: 08/01/2023 02:15:00 UTC