Actively exploited vulnerability
Synacor Zimbra Collaboration Suite (ZCS): vulnerability flaw under attack
CVE-2024-45519 · Synacor Zimbra Collaboration Suite (ZCS) Command Execution Vulnerability
What is affected
Synacor Zimbra Collaboration Suite (ZCS) is mostly run by companies, schools and public bodies, not on home computers. You are unlikely to have it yourself, but organisations that hold your data may. Breaches that start with flaws like this one are how personal data ends up leaked.
Synacor Zimbra Collaboration Suite (ZCS) contains an unspecified vulnerability in the postjournal service that may allow an unauthenticated user to execute commands.
What an attacker can do
This is a vulnerability flaw. It lets an attacker misuse the product in a way its maker did not intend. CISA lists it because attackers are confirmed to be using it against real systems.
- How it is reached
- Over the internet or network
- Access the attacker needs
- No account needed
- Does the victim have to do something?
- No, works without the victim doing anything
What to do
- At home: nothing to install. Keep your own devices updated and use a different password for every service, so that a breach at one organisation does not open your other accounts.
- If you administer Synacor Zimbra Collaboration Suite (ZCS) at work: apply the vendor's fix or mitigation now and review logs for signs of compromise, because the flaw was being exploited before it was listed.
- If the product is past its support date and no fix exists, take it off the internet or retire it.
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Vendor advisories and fixes
- wiki.zimbra.comwiki.zimbra.com/wiki/Zimbra_Security_Advisories
How urgent is it
CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on October 3, 2024, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by October 24, 2024, a deadline that has already passed. That deadline does not bind anyone else, but it shows how seriously the agency rates it.
The EPSS model estimates a 100% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 100.0% of all scored vulnerabilities.
Its CVSS severity score is 9.8 out of 10 (critical), as recorded in the US National Vulnerability Database.
Technical description
The postjournal service in Zimbra Collaboration (ZCS) before 8.8.15 Patch 46, 9 before 9.0.0 Patch 41, 10 before 10.0.9, and 10.1 before 10.1.1 sometimes allows unauthenticated users to execute commands.