A critical vulnerability in Zoho’s widely used compliance tool, ManageEngine ADAudit Plus, which monitors changes to Microsoft Active Directory, leaves endpoints vulnerable to unauthenticated users. A successful exploit could allow an attacker to take over an entire enterprise network, Horizon3.ai researchers warn.
ADAudit Plus offers a path into an organization’s workstations, servers, and file servers, giving IT admins access to a range of users, groups, permissions, and login credentials, as well as security policies. ADAudit Plus also enables users to collect security events from agents running on other machines in the domain through endpoints that agents use to upload events.
The platform’s ability to offer deep access into a company’s internal IT ecosystem heightens the potential for a nightmare-scenario level of data exposure in the event of a breach.
The CVE-2022-28219 vulnerability enables malicious actors to easily take over a network for which they already have initial access. Malicious actors could exploit this vulnerability to deploy ransomware, exfiltrate sensitive business data, or disrupt business operations.
They could also then go on to exploit XML External Entities (XXE), Java deserialization, and path traversal vulnerabilities to wreak additional havoc, according to an in-depth analysis this week by Horizon3.ai.
Inside the Vulnerability
Horizon3.ai discovered some of the ADAudit Plus endpoints used for reporting were unauthenticated.
“One of the first things that stood out was the presence of a /cewolf endpoint handled by the CewolfRenderer servlet in the third-party Cewolf charting library,” the analysis states. “This is the same vulnerable endpoint from CVE-2020-10189, reported against ManageEngine Desktop Central.”
It added, “This gave us a large attack surface to work with because there’s a lot of business logic that was written to process these events. While looking for a file-upload vector, we found a path to trigger a blind XXE [XML External Entity injection] vulnerability in the ProcessTrackingListener class, which handles events containing Windows scheduled task XML content.”
The vulnerability was disclosed to Zoho in March, which released a new build, ADAudit Plus 7060, to fix the issue. The patch fixes the vulnerability by removing the /cewolf endpoint altogether, instead using a secure version of DocumentBuilderFactoryin the ProcessingTrackingListener class and requiring authentication in the form of an agent GUID between agents and ADAudit Plus.
High Stakes, Plus Exploitation Difficult to Detect
Horizon3.ai chief architect Naveen Sunkavally explains that ManageEngine products are very common in the enterprise and have been favorite targets of attackers over the years.
“ADAudit Plus is a tool that's used for compliance and auditing, which is a common need for many companies spanning different verticals,” he says. “This vulnerability has been found to be present in many types of environments, from healthcare and technology to construction and local governments.”
Just last fall, ManageEngine ADSelfService Plus, Desktop Central, and ServiceDesk Plus were all actively targeted by attackers using previously undisclosed zero days (CVE-2021-44515, CVE-2021-44077, and CVE-2021-40539) that are now part of the CISA Known Exploited Vulnerabilities (KEV) list.
The latest vulnerability is easy to exploit without any prior knowledge and can yield the "keys to the kingdom, Sunkavally explains. To boot, exploitation is not that easy to detect because it makes use of the natural behavior of the ADAudit Plus application.
“ADAudit Plus is an attractive target for attackers because it integrates with Active Directory and stores high-privileged domain user credentials,” Sunkavally says.
He notes an attacker with initial access to a compromised network could exploit this vulnerability to extract these high-privileged credentials, move laterally, and take over the entire network.
“We've seen real-world environments where just exploiting this vulnerability alone is enough to take over the enterprise,” Sunkavally adds.
He advises businesses using ADAudit Plus to upgrade to build 7060 or later and ensure ADAudit Plus is configured with a dedicated service account with restricted privileges.
“This vulnerability is not one to hold off on patching,” he says.
Buggy ManageEngine Has History of Vulnerabilities
This is not the first time the ManageEngine suite was found to have vulnerabilities. Last September a joint advisory from the FBI and CISA warned of APT attackers exploiting a critical authentication bypass vulnerability in ManageEngine ADSelfService Plus.
While Zoho moved to fix the vulnerabilities, less than a month later Palo Alto Networks issued a warning that many companies are still vulnerable.
Most recently, an elusive attack targeting SolarWinds' Orion network management software, dubbed the Supernova cyberattack, exploited a ManageEngine flaw in the software running on a victim's server.