CVE-2023-48432 in Zimbra Collaboration Suite
Summary
by MITRE • 02/13/2024
An issue was discovered in Zimbra Collaboration (ZCS) 8.8.15, 9.0, and 10.0. XSS, with resultant session stealing, can occur via JavaScript code in a link (for a webmail redirection endpoint) within en email message, e.g., if a victim clicks on that link within Zimbra webmail.
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Analysis
by VulDB Data Team • 04/19/2025
The vulnerability identified as CVE-2023-48432 represents a critical cross-site scripting flaw within Zimbra Collaboration Suite versions 8.8.15, 9.0, and 10.0. This security weakness specifically targets the webmail redirection endpoint functionality, creating a pathway for malicious actors to execute unauthorized JavaScript code within the context of a victim's browser session. The vulnerability stems from inadequate input validation and output encoding mechanisms within the email processing pipeline, particularly when handling link parameters that are subsequently used for webmail navigation.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious email containing a specially crafted link with embedded JavaScript code within the redirection endpoint parameters. When a victim clicks on such a link while logged into their Zimbra webmail account, the malicious JavaScript executes in the victim's browser context, potentially allowing attackers to steal session cookies, hijack user sessions, or perform unauthorized actions on behalf of the victim. This type of vulnerability falls under CWE-79 which specifically addresses Cross-Site Scripting flaws in web applications, and aligns with ATT&CK technique T1566.001 for Initial Access through Spearphishing Attachment.
The operational impact of CVE-2023-48432 extends beyond simple script execution, as it enables session hijacking and persistent unauthorized access to user accounts. Attackers can leverage this vulnerability to gain full access to victim email accounts, potentially leading to data exfiltration, credential theft, and further lateral movement within organizational networks. The attack vector is particularly concerning because it requires minimal user interaction beyond clicking a malicious link, making it highly effective for social engineering campaigns. Organizations utilizing these affected Zimbra versions face significant risk of unauthorized access to sensitive email communications and personal data stored within their email infrastructure.
Mitigation strategies for CVE-2023-48432 should prioritize immediate patching of affected Zimbra Collaboration Suite versions to the latest available releases that contain the necessary security fixes. Organizations should also implement additional defensive measures including email content filtering to identify and block suspicious links, enhanced web application firewall rules to detect and prevent XSS payloads, and user education programs to raise awareness about phishing attempts. Network-level protections such as DNS-based filtering and secure email gateways can provide additional layers of defense against exploitation attempts. Security teams should conduct thorough vulnerability assessments to ensure all Zimbra installations are properly updated and monitor for any signs of exploitation attempts within their network traffic. The remediation process should also include reviewing and strengthening input validation mechanisms within the email processing pipeline to prevent similar vulnerabilities from emerging in the future.