CVE-2023-29542: Newline Character in Filename Exploit in Firefox and Thunderbird on Windows

A recently discovered vulnerability has been identified in Firefox and Thunderbird on Windows with the identifier CVE-2023-29542. This vulnerability lies within the file extension security mechanisms, allowing malicious actors to bypass them and possibly execute malicious code. This bug only impacts Firefox and Thunderbird on Windows; other versions remain unaffected. The vulnerability affects Firefox versions below 112, Firefox ESR versions below 102.10, and Thunderbird versions below 102.10.

Summary

The vulnerability discovered in Firefox and Thunderbird on Windows systems is related to the handling of newlines in filenames. By including a newline in a filename, attackers can bypass the file extension security mechanisms that are typically in place to replace potentially dangerous file extensions such as .lnk with the safer alternative .download.

Here's a code snippet that demonstrates how this exploit works

# A simple example of a malicious file with a newline character
malicious_file = "example_malicious_file.lnk\n.download"

When a user accidentally executes the malicious file with the newline character included, the system may not recognize the file as a .download file and could execute the malicious code instead.

For further details regarding this vulnerability, check the following references

1. Mozilla Security Advisory - https://www.mozilla.org/en-US/security/advisories/mfsa2023-XX/
2. CVE Details - https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-29542
3. National Vulnerability Database (NVD) - https://nvd.nist.gov/vuln/detail/CVE-2023-29542

Mitigation

To protect yourself and your systems from this exploit, it is highly recommended that you update Firefox and Thunderbird on your Windows systems to the latest versions. The vulnerability is patched in Firefox 112, Firefox ESR 102.10, and Thunderbird 102.10.

- Update Firefox: https://www.mozilla.org/en-US/firefox/new/
- Update Firefox ESR: https://www.mozilla.org/en-US/firefox/organizations/all/#esr
- Update Thunderbird: https://www.thunderbird.net/en-US/

Conclusion

It is essential to keep your software and systems updated to protect against known vulnerabilities like CVE-2023-29542. By updating Firefox and Thunderbird on your Windows system, you help ensure that your browsing experience and email communications remain safe and secure from potential exploitation. Stay vigilant, and always update your software to the latest available versions.

Timeline

Published on: 06/19/2023 11:15:00 UTC
Last modified on: 06/27/2023 08:51:00 UTC