Joint CyberSecurity Advisory on Vulnerabilities in Zimbra Collaboration (CISA-MS-ISAC)


On August 16th, a joint cybersecurity advisory was issued by the Cybersecurity and Infrastructure Security Agency (CISA) and the Multi-State Information Sharing and Analysis Center (MS-ISAC) on vulnerabilities in Zimbra Collaboration that is actively leveraged in the field by threat actors. The advisory covers five CVEs: CVE-2022-24682, CVE-2022-27924, CVE-2022-27925, CVE-2022-37042, and CVE-2022-30333.

Why is this Significant?

This is significant because the vulnerabilities in Zimbra Collaboration Suite called out in the advisory (CVE-2022-24682, CVE-2022-27924, CVE-2022-27925, CVE-2022-37042, and CVE-2022-30333) are leveraged in real attacks by threat actors, and as such relevant patches should be applied as soon as possible.

Zimbra Collaboration, formerly known as Zimbra Collaboration Suite, is a cloud-based email, calendaring, and groupware solution developed by Synacor and is widely used worldwide. According to its Web site, Zimbra is used in more than 140 countries and over 1,000 government and financial institutions.

How Widespread are the Attacks Leveraging the Vulnerabilities?

While there is no information available as to how widespread the attacks are, wide adoption of Zimbra Collaboration is a high exploitation target for any threat actor.

What are the Vulnerabilities Exploited in the Field?

The advisory states a total of five vulnerabilities are exploited in the wild.

  • CVE-2022-24682

CVE-2022-24682 is a cross-site scripting (XSS) vulnerability in Zimbra Webmail. The vulnerability affects all versions of Zimbra 8.8.15 and was exploited as a zero-day. Remote attackers can leverage the vulnerability to run an arbitrary web script within the session of the connected Zimbra user.

  • CVE-2022-27924

CVE-2022-27924 is a memcache command injection vulnerability that impacts Zimbra Collaboration 8.8.15 and 9.0. Successful exploitation allows a remote attacker to steal email login credentials in plain text from Zimbra Collaboration without any user interaction.

  • CVE-2022-27925

CVE-2022-27925 is an arbitrary file upload vulnerability that affects Zimbra Collaboration 8.8.15 and 9.0. By leveraging the vulnerability, an authenticated remote attacker can upload arbitrary files to an arbitrary location on the vulnerable system. The advisory states that CVE-2022-27925 was observed to have been exploited in conjunction with CVE-2022-37042.

  • CVE-2022-37042

CVE-2022-37042 is an authentication bypass vulnerability that impacts Zimbra Collaboration 8.8.15 and 9.0. Successful exploitation allows an unauthenticated attacker to upload arbitrary files to an arbitrary location on the vulnerable system and leads to remote code execution. The advisory states that CVE-2022-37042 was observed to have been exploited in conjunction with CVE-2022-27925.

  • CVE-2022-30333

CVE-2022-30333 is a path traversal vulnerability that affects Linux and Unix versions of RARLAB UnRAR before version 6.12. Successfully exploiting the vulnerability allows an attacker to drop files to an arbitrary location on a vulnerable system during the unpacking operation.

Has the Vendor Released a Patch?

Yes. A patch is available for all vulnerabilities. For more details, see the Appendix for a link to "Zimbra Collaboration - Security Vulnerability Advisories" and "RARLAB".

What is the Status of Coverage?

FortiGuard Labs has the following IPS coverage in place against the exploitation of the vulnerabilities:

  • Zimbra.Collaboration.Calendar.Reflected.XSS (CVE-2022-24682)
  • Zimbra.Collaboration.Mboximport.Unrestricted.File.Upload (CVE-2022-27925 and CVE-2022-37042)
  • Zimbra.Collaboration.Memcached.CRLF.Injection (CVE-2022-27924)
  • RARLAB.UnRAR.ExtractUnixLink50.Directory.Traversal (CVE-2022-30333) - default action is set to "pass"

description-logoOutbreak Alert

Zimbra Collaboration Suite (ZCS) 8.8.15 and 9.0 has mboximport functionality that receives a ZIP archive and extracts files. By bypassing authentication, an attacker can upload arbitrary files to the system, leading to directory traversal and remote code execution. The vulnerability exists due to an incomplete fix for CVE-2022-27925.

View the full Outbreak Alert Report