A security vulnerability, identified as CVE-2024-11706, has recently come to light, potentially impacting older versions of Firefox (prior to version 133) and Thunderbird (prior to version 133). This newly discovered flaw pertains to a possible null pointer dereference encountered within the SEC_ASN1DecodeItem_Util function found in the pk12util – a utility used for importing and exporting certificates and keys between NSS databases.

In this post, we'll delve into the specifics of this vulnerability, highlighting the code snippets where the issues arise, the original references, and the potential exploit scenarios brought about by this null pointer dereference issue.

The pertinent code inside the SEC_ASN1DecodeItem_Util function may appear like this

SEC_ASN1DecoderContext *dec;
. . .
err = PORT_GetError();
if (err == SEC_ERROR_BAD_DER) {
    goto loser;
}
. . .
dec = decoder_util(src, len, dest);
if ( dec != NULL ) {
    PORT_SetError(SEC_ERROR_BAD_DER);
}

- Mozilla Foundation Security Advisory 2024-45
- Bugzilla Entry for CVE-2024-11706
- National Vulnerability Database (NVD) Entry for CVE-2024-11706

Exploit Details

In order to exploit this vulnerability, an attacker would need to craft a malicious input file and give it to a user leveraging the vulnerable versions of Firefox or Thunderbird. The input file's formatting should be such that it would lead to the null pointer dereference within the SEC_ASN1DecodeItem_Util function, potentially resulting in a crash or other undefined behavior – potentially opening the door to further exploitation.

Upon receiving the malformed input file, the targeted user would then proceed to import the attacker's certificate or key by using the pk12util tool. If the user is running a version of Firefox or Thunderbird listed as vulnerable, the null pointer dereference would be triggered.

Mitigation and Recommendations

To successfully mitigate this vulnerability, it is advised to update to the latest version of Firefox (version 133 or higher) and Thunderbird (version 133 or higher). Keeping software up-to-date helps to minimize the risk of encountering such security issues and safeguarding from potential exploits.

As a general rule, users should also exercise caution when importing certificates and keys, especially if they are received from untrusted sources. Requesting certificates from verified sources and double-checking the authenticity of said certificates can help to significantly reduce the risks associated with this sort of vulnerability.

By staying current on software updates and maintaining a vigilant approach to handling sensitive files, users can primarily avoid the threats posed by CVE-2024-11706 and similar null pointer dereference vulnerabilities.

Timeline

Published on: 11/26/2024 14:15:20 UTC
Last modified on: 11/26/2024 17:15:23 UTC