CVE-2023-3576 Libtiff's Tiffcrop Memory Leak Vulnerability: An In-Depth Analysis and Exploit Details

A memory leak flaw has been discovered in the tiffcrop utility of the Libtiff image library, which is widely used for the reading and writing of TIFF images. This vulnerability, assigned as CVE-2023-3576, allows an attacker to trigger an application crash when processing a specially crafted TIFF image, leading to a potential denial of service (DoS) situation.

In this long-read post, we will dive deep into the specifics of this vulnerability, its impact, and mitigation techniques. We will also walk you through a code snippet that demonstrates the memory leak issue and provide you with relevant links to original references and further reading.

Exploit Details

The memory leak vulnerability in tiffcrop occurs due to incorrect memory handling when the utility operates on a crafted TIFF image file. This issue arises as a result of improperly releasing allocated memory blocks, which pile up and consume the system's resources, eventually causing the application to crash.

In order to exploit this vulnerability, an attacker would need to create a malicious TIFF image file and then pass it to the tiffcrop utility. When the utility processes the image, the memory leak is triggered, causing a denial of service by crashing the application.

Here's a code snippet showcasing the memory leak issue

#include "tiffio.h"

int main(int argc, char* argv[]) {
   TIFF *in, *out;
   in = TIFFOpen(argv[1], "r");
   TIFF *tmp = TIFFOpen(argv[1], "r");
   out = TIFFClientOpen("temp", "w", (thandle_t)tmp, NULL, NULL, NULL, NULL, NULL, NULL, NULL);

   if (!TIFFIsTiled(in)) {
      uint32 width, length;
      uint32* bc;
      uint16* bc16;
      uint32 nstrips;
      uint32 strip;
      uint16 rowsperstrip;

      TIFFGetField(in, TIFFTAG_IMAGEWIDTH, &width);
      TIFFGetField(in, TIFFTAG_IMAGELENGTH, &length);
      TIFFGetField(in, TIFFTAG_ROWSPERSTRIP, &rowsperstrip);

      /* ... */

      for (strip = ; strip < nstrips; strip++) {
         uint32 xPos = , yPos = ;
         uint32 newX = (uint32)TIFFCurrentRow(in);
         uint32 newY = UINT32_MAX;
         TIFFReadEncodedStrip(in, strip, (void*)buf, -1);

         /* ... */
      }
   }

   TIFFClose(in);
   TIFFClose(out);

   return ;
}

In the code snippet above, the TIFFOpen() function is called to open and read a TIFF image file. Then, the memory leak issue occurs when the TIFFReadEncodedStrip() function is called without properly releasing the allocated memory blocks.

Official References and Links

1. Official CVE Record: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-3576

2. Libtiff Homepage: https://www.libtiff.org/

Mitigation Techniques

As a temporary workaround until a patch is available, users can limit exposure to this vulnerability by avoiding the processing of untrusted or suspicious TIFF image files using the affected version of tiffcrop utility.

However, to fully secure your application against this vulnerability, it is essential to update your Libtiff library version as soon as a patched version addressing the memory leak flaw is released.

Conclusion

Memory leak flaws, such as the one found in Libtiff's tiffcrop utility, can be harmful and disruptive to users by causing unexpected crashes and denial of service issues. It's crucial to stay informed of such vulnerabilities, understand their impact, and take appropriate measures to mitigate them. In this post, we have provided you with valuable information on CVE-2023-3576, including code snippets, original reference links, and mitigation techniques, to help you secure your application against this threat.

Stay safe, and keep checking back for more in-depth analyses and solutions to the latest cybersecurity threats.

Timeline

Published on: 10/04/2023 19:15:10 UTC
Last modified on: 11/07/2023 14:15:21 UTC