CVE-2018-6882 Scanner

The Zimbra Collaboration Suite (ZCS) is a widely-used email and collaboration software solution designed for organizations and individuals looking to improve their communication capabilities. ZCS integrates various tools like email, calendar, contacts, and document management, making it suitable for businesses, educational institutions, and even government agencies. It provides a platform where users can manage communications, store contacts, and schedule meetings, helping streamline workflows. ZCS is preferred by IT administrators for its flexible deployment options, including on-premises and cloud-based implementations. With its robust set of APIs and integration capabilities, ZCS can easily adapt to different IT environments. Many organizations rely on ZCS for its open-source nature, providing transparency and customization options.

Cross-Site Scripting (XSS) is a common vulnerability that occurs when an application includes untrustworthy data in a web page without proper validation or escaping. In this context, XSS in Zimbra Collaboration Suite was identified in the ZmMailMsgView.getAttachmentLinkHtml function. The vulnerability arises because the application fails to sanitize the Content-Location header in email attachments thoroughly. Attackers could exploit this flaw to execute arbitrary web scripts in the context of a user's browser session. XSS vulnerabilities pose a significant risk as they can lead to unauthorized actions on behalf of the user. This vulnerability particularly targets the user's browser environment, making it a client-side threat.

The technical specifics of this vulnerability are centered around handling email attachments in ZCS, particularly exploiting the Content-Location header. When exploited, the injection point allows attackers to insert malicious scripts that are executed when the user interacts with a crafted email. The attack vector requires the attacker to send an email to the target with an attachment that includes the crafted Header. When users open the email, the browser executes the unauthorized script code. The flaw is rooted in insufficient sanitization and validation of user-controlled input that interacts with the email system's rendering library.

If an attacker successfully exploits this XSS vulnerability, it can lead to several severe outcomes. For instance, attackers could execute scripts that perform harmful actions like stealing user session tokens, redirecting users to malicious sites, or even logging their keystrokes. The exploitation could further result in unauthorized access to the email system, leading to data leakage or manipulation. In a worst-case scenario, full account compromise is possible, significantly impacting the organization's communication infrastructure. Additionally, it could tarnish the organization's reputation among users who otherwise rely on the integrity and security of ZCS.

REFERENCES

• https://www.securify.nl/advisory/SFY20180101/cross-site-scripting-vulnerability-in-zimbra-collaboration-suite-due-to-the-way-it-handles-attachment-links.html
• https://nvd.nist.gov/vuln/detail/CVE-2018-6882