SB2018082107 - Multiple vulnerabilities in Nextcloud Server
Published: August 21, 2018
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 3 vulnerabilities.
1) Cross-site scripting (CVE-ID: CVE-2018-3780)
CWE-ID: CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U/U:Clear
The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.
The vulnerability exists due to insufficient sanitization of user-supplied data. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website.
Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.
2) Improper authentication (CVE-ID: CVE-2018-3775)
CWE-ID: CWE-287 - Improper Authentication
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
The disclosed vulnerability allows a remote attacker to bypass authentication on the target system.
The vulnerability exists due to improper authentication. A remote authenticated attacker that obtained user credentials can bypass the 2 Factor Authentication.
3) Improper input validation (CVE-ID: CVE-2018-3776)
CWE-ID: CWE-20 - Improper input validation
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
The disclosed vulnerability allows a remote attacker to bypass security restrictions on the target system.
The vulnerability exists due to insufficient sanitization of user-supplied data passed to JSON encoder. A remote attacker can cause attacker's actions not being logged in the audit log.
Remediation
Install update from vendor's website.