CVE-2017-0893 : Security Advisory and Response

Nextcloud Server versions before 9.0.58, 10.0.5, and 11.0.3 contain an XSS vulnerability due to a JavaScript library issue.

Understanding CVE-2017-0893

This CVE involves a Cross-Site Scripting (XSS) vulnerability in Nextcloud Server versions before specific updates.

What is CVE-2017-0893?

Nextcloud Server versions prior to 9.0.58, 10.0.5, and 11.0.3 are equipped with a vulnerable JavaScript library susceptible to XSS attacks caused by Safari behavior changes.
Nextcloud's Content-Security-Policy helps prevent exploitation on modern browsers.

The Impact of CVE-2017-0893

Malicious actors can execute arbitrary scripts in the context of a user's browser, potentially leading to unauthorized actions.

Technical Details of CVE-2017-0893

This section provides in-depth technical insights into the vulnerability.

Vulnerability Description

The XSS vulnerability arises from a flawed JavaScript library used for sanitizing user input.

Affected Systems and Versions

Product: Nextcloud Server
Vendor: Nextcloud
Vulnerable Versions: Before 9.0.58, 10.0.5, and 11.0.3

Exploitation Mechanism

Exploitation involves injecting malicious scripts into web pages viewed by users, taking advantage of the XSS vulnerability.

Mitigation and Prevention

Protect your systems from CVE-2017-0893 with the following measures:

Immediate Steps to Take

Update Nextcloud Server to versions 9.0.58, 10.0.5, or 11.0.3 to mitigate the XSS vulnerability.
Regularly monitor security advisories from Nextcloud for any future vulnerabilities.

Long-Term Security Practices

Implement strict Content-Security-Policy settings to mitigate XSS risks.
Educate users on safe browsing practices to minimize the impact of XSS attacks.

Patching and Updates

Apply security patches promptly to address known vulnerabilities and enhance system security.