CVE-2021-44515: ZoHo Patches ManageEngine Zero-Day Exploited in the Wild

ZoHo has released patches for an authentication bypass vulnerability that could lead to remote code execution and has been exploited in the wild.

Background

On December 3, ZoHo issued a security advisory and patches for CVE-2021-44515, an authentication bypass vulnerability in its ManageEngine Desktop Central product that has been exploited in the wild. In addition, a patch was released for CVE-2021-44526, another authentication bypass vulnerability in ServiceDesk Plus, a help desk and asset management application.

This follows months of reports and alerts regarding active exploitation of two other vulnerabilities in ManageEngine products, CVE-2021-44077 and CVE-2021-40539. The attacks exploiting these vulnerabilities have been linked to advanced persistent threat (APT) groups.

On September 16, the Federal Bureau of Investigation (FBI), United States Coast Guard Cyber Command (CGCYBER), and the Cybersecurity and Infrastructure Security Agency (CISA) first alerted the public of activity targeting CVE-2021-40539, stating it was likely APT activity and highlighting the elevated risks these attacks posed to critical infrastructure. The alert also mentions that attacks were traced back as early as August. Following the joint alert, Palo Alto Networks’ Unit 42 observed a separate group targeting CVE-2021-40539 in order to gain access to sensitive files in the target environment.

Also on September 16, ZoHo patched CVE-2021-44077 in ManageEngine ServiceDesk Plus. On November 22, ZoHo published an advisory warning of active exploitation. CISA and the FBI, as well as Unit 42 published advisories on December 2 outlining the exploitation activity observed.

At the time of publication, specific information has not been provided about the attacks exploiting CVE-2021-44515.

Analysis

CVE-2021-44515 is an authentication bypass vulnerability in ManageEngine Desktop Central that could lead to remote code execution. To exploit, an attacker would send a specially crafted request to a vulnerable endpoint.

CVE-2021-44526 is another authentication bypass vulnerability that was patched on December 3. It exists in ServiceDesk Plus on-premises versions up to 12002. The vulnerability exists due to a flaw in the application filters used in the list view. Using a crafted URL, an attacker can access a servlet that should only be available to an authenticated user.

CVE-2021-44077 is an unauthenticated remote code execution vulnerability in ManageEngine ServiceDesk Plus caused by a security misconfiguration. It affects on-premises deployments up to version 11306.

CVE-2021-40539 is a representational state transfer (REST) application programming interface (API) authentication bypass vulnerability in ManageEngine ADSelfService Plus. A remote, unauthenticated attacker could exploit this vulnerability by sending a specially crafted request to a vulnerable host. Successful exploitation would grant an attacker remote code execution. It was patched on September 6 in build 6114. CVE-2021-40539 has been exploited to deploy webshells and establish persistence in target environments.

Proof of concept

Despite the active exploitation of these vulnerabilities, there aren’t any known public proofs-of-concept available as of December 6.

Solution

ZoHo has issued patches for all of these vulnerabilities. Several of the advisories include specific guidance on how to determine the appropriate update path.

Identifying affected systems

A list of Tenable plugins to identify these vulnerabilities will appear here as they’re released.

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