Cisco this week announced that it has patched two actively exploited Salt vulnerabilities, but not before malicious actors leveraged the flaws to hack some of the company’s servers.
Rated critical, the vulnerabilities, tracked as CVE-2020-11651 and CVE-2020-11652, were made public at the end of April, when SaltStack patches were released. The issue, however, only appears when unsecure settings are used.
The popular configuration tool uses a Salt Master to collect reports from agents called minions, and to deliver messages (configuration updates) to them. Typically, the Salt Master is not connected to the Internet, but roughly 6,000 instances were found exposed at the end of April.
The critical vulnerability that was found in Salt Master version 2019.2.3 and Salt 3000 versions 3000.1 and earlier could be abused by unauthenticated attackers to gain root-equivalent access to the Salt Master.
Within days after the patches arrived, the first attacks targeting the vulnerability were observed, with search provider Algolia and LineageOS, Ghost, and DigiCert servers quickly falling victims due to the lack of timely patching.
Now, Cisco reveals that salt-master servers that are used with Cisco Virtual Internet Routing Lab Personal Edition (VIRL-PE) were upgraded on May 7, and that, on the same day, they were found to have been compromised through the aforementioned vulnerabilities.
“Cisco identified that the Cisco maintained salt-master servers that are servicing Cisco VIRL-PE releases 1.2 and 1.3 were compromised. The servers were remediated on May 7, 2020,” the company announced in an advisory.
The hackers gained access to six servers, including us-1.virl.info, us-2.virl.info, us-3.virl.info, us-4.virl.info, vsm-us-1.virl.info, and vsm-us-2.virl.info, Cisco says.
“Cisco VIRL-PE connects back to Cisco maintained Salt Servers that are running the salt-master service. These servers are configured to communicate with a different Cisco salt-master server, depending on which release of Cisco VIRL-PE software is running. Administrators can check the configured Cisco salt-master server by navigating to VIRL Server > Salt Configuration and Status,” the company explains.
Cisco Modeling Labs Corporate Edition (CML), which is also impacted by the Salt vulnerabilities, does not connect to Cisco-maintained Salt Servers. The company explains that, for CML and VIRL-PE software releases 1.5 and 1.6, exploitability of enabled salt-master services depends on whether the salt-master service is reachable on TCP ports 4505 and 4506.
“For any installation that is found with salt-master service running Cisco would recommend either inspecting the machine for compromise or doing a re-image of the machine and installing the latest version of Cisco CML or Cisco VIRL-PE,” the company adds.
Cisco CML and Cisco VIRL-PE can be deployed in both standalone and cluster modes, and impact depends on the deployment type. Versions 2.0 of both CML and VIRL-PE are not affected, because they do not run the salt-master service.
For versions 1.6, there’s no impact when performing a fresh install, as the salt-master service is not running in standalone mode, or runs on a private network in cluster mode. When upgrading from version 1.5, however, the salt-master service is running.
For versions 1.5 and earlier, the salt-master service is running, and customers are advised to upgrade to a patched release.