Post Syndicated from Tod Beardsley original https://blog.rapid7.com/2022/12/07/cve-2022-4261-rapid7-nexpose-update-validation-issue-fixed/

On November 14, 2022, Rapid7’s product engineering team discovered that the mechanism used to validate the source of an update file was unreliable. This failure involving the internal cryptographic validation of received updates was designated as CVE-2022-4261, and is an instance of CWE-494. Rapid7’s estimate of the CVSSv3.1 base rating for this vulnerability for most environments is 4.4 (Medium). This issue is resolved in the regular December 7, 2022 release.

Product Description

Rapid7 Nexpose is an on-premise vulnerability scanner, used by many enterprises around the world to assess and manage the vulnerability exposures present in their networks. You can read more about Nexpose at our website.

Note that CVE-2022-4261 only affects the on-premise Nexpose product, and does not affect InsightVM.

Credit

This issue was discovered by Rapid7 Principal Software Engineer Emmett Kelly and validated by the Rapid7 Nexpose product team. It is being disclosed in accordance with Rapid7’s vulnerability disclosure policy.

Exploitation

Exploitation of this issue is complex, and requires an attacker already in a privileged position in the network. By understanding these complications, we believe our customers will be better able to make appropriate judgements on the risk of delaying this update, perhaps due to established change control procedures.

In order to exploit CVE-2022-4261, an attacker would first need to be in a position to provide a malicious update to Nexpose, either through a privileged position on the network, on the local computer that runs Nexpose (with sufficient privileges to initiate an update), or by convincing a Nexpose administrator to apply a maliciously-crafted update through social engineering. Once applied, the update could introduce new functionality to Nexpose that would benefit the attacker.

Impact

Given the requirement of a privileged position on the network or local machine, exploiting CVE-2022-4261, in most circumstances, is academic. Such an adversary is likely to already have many other (and often easier) choices when it comes to leveraging this position to cause trouble on the target network. In the case of a local machine compromise (which is the most likely attack scenario), the attacker could use this position to instead create a fairly permanent ingress avenue to the internal network and exercise the usual lateral movement options documented as ATT&CK technique T1557.

Remediation

Disabling automatic updates completely removes the risk of exploitation of CVE-2022-4261. That said, most Nexpose administrators already employ Nexpose’s automated updates, and should apply updates either on their already established automated schedules or as soon as it’s convenient to do so.

Nexpose administrators that are especially concerned that they will be targeted during their next update, or who believe they have already been compromised by persistent attackers, should disable automatic updates and use the documented Managing Updates without an Internet Connection procedure to fix this issue, after manually validating the authenticity of the update package.

Fixing an update system with an update is always fairly complex, given the chicken-and-egg nature of the problem being addressed, as well as the risks involved in using an update system to fix an update system. So, it is out of an abundance of caution that we are publishing this advisory today to ensure that customers who rely on automatic updates are made plainly aware of this issue and can plan accordingly.

Disclosure Timeline

• Mon, Nov 14, 2022: Issue discovered by Emett Kelly, and validated by the Nexpose product team.
• Thu, Dec 1, 2022: CVE-2022-4261 reserved by Rapid7.
• Wed, Dec 7, 2022 : This disclosure and update 6.6.172 released.