SB2021012515 - Multiple vulnerabilities in Moodle
Published: January 25, 2021
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 5 secuirty vulnerabilities.
1) Cross-site scripting (CVE-ID: CVE-2021-20183)
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 in certain search inputs. 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 access control (CVE-ID: CVE-2021-20184)
The vulnerability allows a remote user to gain unauthorized access to otherwise restricted functionality.
The vulnerability exists due to improper access restrictions in grade related web services. A remote user with student access can view grades of other students.
3) Resource management error (CVE-ID: CVE-2021-20185)
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to the application does not impose limits on the number of characters sent via messages. A remote user can send an overly long message and perform a client-side (browser) denial of service attack.
4) Stored cross-site scripting (CVE-ID: CVE-2021-20186)
The disclosed vulnerability allows a remote user to perform cross-site scripting (XSS) attacks.
The vulnerability exists due to insufficient sanitization of user-supplied data in the TeX notation filter. A remote user can inject 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.
5) PHP file inclusion (CVE-ID: CVE-2021-20187)
The vulnerability allows a remote administrator to include and execute arbitrary PHP files on the server.
The vulnerability exists due to incorrect input validation when including PHP files during Shibboleth authentication. A remote administrator can include and execute arbitrary PHP code on the system with privileges of the web server.
Remediation
Install update from vendor's website.