Horizon Alert
Summary of the vulnerability and why it matters
Concrete CMS versions prior to 9.5.1 contain a flaw that, if exploited, could allow an attacker to execute arbitrary code on the affected system. This occurs when an attacker manipulates a remote package update request, causing the system to process a malicious package and execute its code. The potential impact includes unauthorized code execution on the web server, which could compromise data and disrupt business operations.
- Vulnerable component: Concrete CMS package update feature
- Core weakness: Improper validation of update requests
- Main business impact: Remote code execution on web server
Attack Path
How an attacker could exploit the issue
An attacker can exploit a Cross-Site Request Forgery (CSRF) vulnerability in Concrete CMS to execute arbitrary code. This occurs when a user visits a malicious link, which tricks their browser into sending a crafted request to the Concrete CMS. If the target site is connected to the Concrete marketplace and has specific packages installed, the attacker can manipulate the response from the marketplace to overwrite existing package files. This ultimately leads to the execution of the `upgrade()` method, allowing the attacker to run code as the web server user.
- Remote marketplace, CSRF token bypass.
- Attacker controls marketplace package.
- User navigates malicious link.
- Remote code execution occurs.
Live Threat
Current exploitation, exposure, and threat context
The identified vulnerability in Concrete CMS could allow an attacker to execute arbitrary code on the web server. This occurs when an attacker controls a remote package that is then processed by an affected Concrete CMS site connected to the Concrete marketplace, after the victim interacts with a malicious link. Successful exploitation could lead to unauthorized code execution and compromise of the web server.
- Likely attacker skill level: High
- Required access or conditions: Marketplace connection, user interaction
- Business risk or urgency: High impact, requires specific conditions
Priority actions
Operational Fix
Recommended remediation, mitigation, and detection steps
This vulnerability in Concrete CMS allows for remote code execution if specific conditions are met, including the organization's site being connected to the Concrete marketplace and an attacker controlling a marketplace package. Exploitation can lead to the compromise of the web server user. The risk is present for systems using affected versions of Concrete CMS that are configured for remote package upgrades and where the marketplace item ID is known.
- Identify Concrete CMS assets using affected versions.
- Restrict marketplace connections and package upgrade privileges.
- Update Concrete CMS to the vendor-provided fix and validate.
- Monitor systems for unauthorized activity.
