"CVE-2023-43115: Understanding the Remote Code Execution Vulnerability in Artifex Ghostscript 10.01.2 through GhostPDL's gdevijs.c"

The recent discovery of a security vulnerability within Artifex Ghostscript's gdevijs.c module, identified as CVE-2023-43115, presents a potential remote code execution (RCE) risk. This vulnerability affects Artifex Ghostscript versions 10.01.2 and potentially prior versions. Ghostscript is an interpreter for the PostScript programming language and PDF file format; it is widely used in both software and hardware devices.

In this post, we will discuss the root cause of the vulnerability, the potential impact, available mitigation measures, and reference to the original resources. Additionally, we will cover some insights into the code snippet and exploit details to help concerned parties take proactive measures to protect their systems.

Root Cause

The gdevijs.c module in GhostPDL is responsible for enabling communication between Ghostscript and the IJS server. However, a flaw exists in how this module works when SAFER mode is activated. In essence, an attacker with the ability to craft malicious PostScript documents could create a situation where the IJS device switches or changes the IjsServer parameter after the SAFER mode has been enabled, leading to remote code execution.

The following code snippet provides a simplified example of the possible vulnerability

// gdevijs.c Module
if (SAFER_ENABLED) {
    // IJS device initialization
    switch_to_IJS_device();
    
    // ... additional code ...
}

Exploit Details

An attacker would need to create a malicious PostScript document, which when processed by the vulnerable Ghostscript, could trigger the RCE. The IJS server can be specified on a Ghostscript command line, allowing it to inherently execute commands to start the IJS server. For this reason, Ghostscript has previously warned that the IJS server may pose a risk.

Mitigations

The developers of Ghostscript have yet to release an official security update patching this vulnerability. Therefore, organizations concerned about this vulnerability should consider adopting alternative software or intermediate measures until a patch is available. One option may include using isolated environments. Users should ideally consult their software vendors or hardware manufacturers for their advice on how to proceed.

Original References

CVE-2023-43115 has been documented in public databases, such as Artifex's own security advisory page and the National Vulnerability Database (NVD). The following links provide useful references to those interested in learning more about this vulnerability:

- Artifex Security Advisory: https://www.artifex.com/security-advisories/
- NVD Reference: https://nvd.nist.gov/vuln/detail/CVE-2023-43115

Conclusion

The CVE-2023-43115 RCE vulnerability in Artifex Ghostscript is a pertinent issue that requires attention. While an official patch has not yet been released, we encourage readers to be proactive and stay vigilant in addressing this security issue by keeping abreast of updates from Ghostscript developers and considering alternative measures if needed. Remember, staying informed and being proactive can help minimize your risk in the face of active security vulnerabilities.

Timeline

Published on: 09/18/2023 08:15:07 UTC
Last modified on: 11/07/2023 04:21:17 UTC