Advisory Details

This vulnerability allows remote attackers to disclose sensitive information on affected installations of Squid Cache. Authentication is not required to exploit this vulnerability.

The specific flaw exists within the handling of the WCCP protocol. The issue results from the lack of proper validation of user-supplied data, which can result in a read past the end of an allocated buffer. An attacker can leverage this in conjunction with other vulnerabilities to execute code in the context of the "nobody" user.

This vulnerability is being disclosed publicly without a patch in accordance with the ZDI 120 day deadline.

08/17/20 – ZDI reported the vulnerability to the vendor
08/17/20 – The vendor acknowledged the report
12/14/20 – ZDI requested an update
12/18/20 – ZDI requested an update
12/18/20 – The vendor indicated they were working on a fix
02/02/21 – ZDI notified the vendor of the intention to publish the case as a 0-day advisory on 02/09/21

-- Mitigation:
Given the nature of the vulnerability the only salient mitigation strategy is to restrict interaction with the application.

• 2020-08-17 - Vulnerability reported to vendor
• 2021-02-09 - Coordinated public release of advisory