CVE-2024-45515: Zimbra Collaboration XSS Vulnerability via Malicious Briefcase Upload
This post details a cross-site scripting (XSS) vulnerability, CVE-2024-45515, affecting Zimbra Collaboration Suite (ZCS) versions up to 10.1. The vulnerability resides in the Zimbra webmail interface and can be exploited by uploading a specially crafted file to the 'Briefcase' feature, allowing attackers to execute arbitrary JavaScript in the victim's browser session. This could lead to account compromise or other malicious activities.
Vulnerability Details
- CVE ID: CVE-2024-45515
- Description: A cross-site scripting (XSS) vulnerability exists in Zimbra Collaboration Suite (ZCS) webmail due to insufficient validation of content type metadata when importing files into the Briefcase. An attacker can exploit this by crafting a file with manipulated metadata to bypass content type checks and execute arbitrary JavaScript within a user's session.
- CVSS Score: 6.1 (Medium)
- CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- CVSS Explanation: This vulnerability has a CVSS score of 6.1, which is considered Medium severity. The attack vector is Network (AV:N), meaning it can be exploited remotely. The attack complexity is Low (AC:L), requiring minimal effort to exploit. No privileges are required (PR:N). User interaction is Required (UI:R), as the victim needs to interact with the malicious file. The scope is Changed (S:C), meaning an attacker can execute code within the security context of the Zimbra domain. The confidentiality impact is Low (C:L), integrity impact is Low (I:L), and availability impact is None (A:N). In essence, an attacker can read limited sensitive information and modify the appearance or behavior of the affected web page, but cannot disrupt service availability.
- Exploit Requirements: An attacker needs to craft a file with malicious metadata and convince a Zimbra user to upload the file to their Briefcase.
- Affected Vendor: Zimbra
- Affected Product: Zimbra Collaboration Suite (ZCS)
- Affected Version: Versions up to 10.1
- CWE: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- CWE Explanation: CWE-79 refers to Cross-Site Scripting (XSS) vulnerabilities. This occurs when an application uses untrusted data to construct a web page without properly validating or encoding it. This allows attackers to inject malicious scripts into the web page, which are then executed by the victim's browser.
Timeline of Events
- Reported: Likely prior to CVE assignment (date unknown)
- CVE Assigned: 2024-45515
- Published: 2025-07-30
- Fixed: Addressed in Zimbra Releases 10.0.9 (See References)
Exploitability & Real-World Risk
This XSS vulnerability poses a real risk as Zimbra Collaboration Suite is widely used by organizations for email and collaboration. An attacker could potentially craft a convincing file (e.g., a fake invoice or document) and trick a user into uploading it. Successful exploitation can lead to session hijacking, where the attacker gains access to the victim's email, contacts, and other sensitive data. It can also be used to spread malware within the organization.
Recommendations
- Upgrade to the latest version of Zimbra Collaboration Suite: Ensure you are running a version that includes the security fix for this vulnerability. Specifically, upgrade to or beyond version 10.0.9.
- Educate Users: Train users to be cautious about uploading files from untrusted sources. Emphasize the importance of verifying the sender and the file's legitimacy before uploading anything.
- Implement Content Security Policy (CSP): Configure CSP to restrict the sources from which the browser can load resources, mitigating the impact of XSS attacks.
Technical Insight
The vulnerability stems from Zimbra's failure to properly validate the content type metadata of files uploaded to the Briefcase. By manipulating this metadata, an attacker can bypass the checks intended to prevent the execution of arbitrary JavaScript code. This allows a malicious file, disguised as a harmless document, to execute JavaScript when accessed within the victim's Zimbra session.
Credit to Researcher(s)
Details regarding the researcher who discovered this vulnerability are currently unavailable. Please refer to Zimbra's security advisories for further information.
References
- Zimbra Security Center
- Zimbra Releases/10.0.9 Security Fixes
- Zimbra Responsible Disclosure Policy
- Zimbra Security Advisories
Tags
#Zimbra #XSS #CrossSiteScripting #CVE202445515 #SecurityVulnerability #Briefcase #Webmail #JavaScript
Summary: CVE-2024-45515 is a medium severity XSS vulnerability in Zimbra Collaboration Suite (ZCS) that allows attackers to execute arbitrary JavaScript code by uploading malicious files to the Briefcase. Users should upgrade to version 10.0.9 or later and exercise caution when handling files from untrusted sources.
CVE ID: CVE-2024-45515
Risk Analysis: Successful exploitation of this XSS vulnerability can lead to session hijacking, allowing attackers to access the victim's email, contacts, and other sensitive data stored within Zimbra. It could also be used to perform actions on behalf of the user or to spread malware within the organization.
Recommendation: Upgrade to Zimbra Collaboration Suite version 10.0.9 or later, which includes a fix for this vulnerability. Educate users about the risks of uploading files from untrusted sources and implement Content Security Policy (CSP) to mitigate the impact of XSS attacks.
Timeline
- 2025-07-30: CVE-2024-45515 published