BaseFortify

Executive Summary

CVE-2024-27443 is a Cross-Site Scripting (XSS) vulnerability in the CalendarInvite feature of the Zimbra webmail classic user interface. It occurs due to improper input validation in handling the calendar header, allowing an attacker to embed malicious JavaScript code in a crafted calendar header within an email. When a victim views this email in the vulnerable Zimbra webmail interface, the malicious script executes in the context of the victim's session, potentially allowing arbitrary JavaScript code execution. ['CVE description']

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Impact Analysis

This vulnerability can be exploited by attackers to execute arbitrary JavaScript code in the context of a victim's webmail session. This can lead to credential theft, data exfiltration of emails and contacts, and potentially bypassing security mechanisms such as two-factor authentication. Specifically, it has been exploited in a cyberespionage campaign (Operation RoundPress) targeting high-value webmail servers, enabling attackers to steal confidential data and gain unauthorized access to email accounts. ['CVE description', 3]

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Mitigation Strategies

To mitigate CVE-2024-27443, immediately apply the security patches provided in Zimbra Collaboration versions 9.0.0 Patch 39 and 10.0.7, which address this Local Privilege Escalation vulnerability. These patches include updates to relevant components and security hardening measures. Additionally, upgrade the Nginx package to version 1.24.0 as included in these releases. Ensure OpenSSL 3.0 is configured with FIPS compliance enabled by default, enforcing TLS 1.2 as the minimum supported version. If issues arise, follow instructions to enable or disable the FIPS provider. Also, verify that any SAML and SSO-based login configurations have the zimbraVirtualHostName parameter set before upgrading. For environments using OpenJDK 17, consider the impact on Kerberos encryption and configure allow_weak_crypto in krb5.conf if necessary, followed by a mailboxd service restart. These steps collectively help mitigate the vulnerability and improve overall security. [1, 2]

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