SB2021072603 - Multiple vulnerabilities in mod_auth_openidc

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Main Vulnerability Database SB2021072603

SB2021072603 - Multiple vulnerabilities in mod_auth_openidc

Published: July 26, 2021 Updated: August 18, 2023

Security Bulletin ID SB2021072603
Severity
Low
Patch available
YES
Number of vulnerabilities 4
Exploitation vector Remote access
Highest impact Denial of service

Breakdown by Severity

Medium 25% Low 75%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 4 secuirty vulnerabilities.


1) Cross-site scripting (CVE-ID: CVE-2021-32792)

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 within the "OIDCPreservePost On". 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) Format string error (CVE-ID: CVE-2021-32785)

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a format string error as mod_auth_openidc wrongly performs argument interpolation before passing Redis requests to `hiredis. A remote attacker can supply a specially crafted input that contains format string specifiers and perform a denial of service (DoS) attack.


3) Use of insufficiently random values (CVE-ID: CVE-2021-32791)

The vulnerability allows a remote attacker to perform a brute-force attack.

The vulnerability exists due to the AES GCM encryption in mod_auth_openidc uses a static IV and AAD, which creates a static nonce. Since aes-gcm is a stream cipher, this can lead to known cryptographic issues as the same key is being reused.


4) Open redirect (CVE-ID: CVE-2021-32786)

The vulnerability allows a remote attacker to redirect victims to arbitrary URL.

The vulnerability exists due to improper sanitization of user-supplied data in oidc_validate_redirect_url() function. A remote attacker can create a link that leads to a trusted website, however, when clicked, redirects the victim to arbitrary domain.

Successful exploitation of this vulnerability may allow a remote attacker to perform a phishing attack and steal potentially sensitive information.


Remediation

Install update from vendor's website.

References