CVE-2022-30287: Horde Groupware RCE Vulnerability

CVE-2022-30287 Overview

CVE-2022-30287 is a reflection injection vulnerability affecting Horde Groupware Webmail Edition through version 5.2.22. The vulnerability allows authenticated attackers to instantiate arbitrary driver classes through improper input validation, which subsequently leads to arbitrary deserialization of PHP objects. This attack chain can potentially enable remote code execution on vulnerable systems.

Critical Impact

Authenticated attackers can exploit reflection injection to trigger arbitrary PHP object deserialization, potentially leading to complete system compromise through remote code execution.

Affected Products

• Horde Groupware Webmail Edition through version 5.2.22
• Debian Linux 10.0

Discovery Timeline

• July 28, 2022 - CVE-2022-30287 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2022-30287

Vulnerability Analysis

This vulnerability is classified under CWE-470 (Use of Externally-Controlled Input to Select Classes or Code), commonly known as unsafe reflection. The flaw exists in Horde Groupware Webmail Edition's handling of user-supplied input when selecting and instantiating driver classes.

When user-controlled data is used to determine which class to instantiate without proper validation, attackers can manipulate this input to select arbitrary classes within the application. In the context of Horde Webmail, this reflection injection vulnerability creates a pathway to trigger PHP's deserialization mechanism with attacker-controlled data.

The attack requires a low-privilege authenticated session and some user interaction, but once exploited, can result in complete compromise of confidentiality, integrity, and availability of the affected system.

Root Cause

The root cause of CVE-2022-30287 lies in insufficient input validation when processing class names or identifiers that control driver instantiation. The application accepts externally-controlled input to select which PHP class should be instantiated, without adequately restricting the allowed classes or sanitizing the input.

This unsafe reflection pattern allows attackers to specify arbitrary class names, which when combined with PHP's class autoloading and instantiation behavior, enables the attacker to trigger deserialization of PHP objects. The deserialization of untrusted data is a well-known attack vector that can lead to remote code execution through PHP gadget chains.

Attack Vector

The attack is conducted over the network and requires the attacker to have low-privilege authentication to the Horde Webmail application. The exploitation chain involves:

1. The attacker authenticates to the Horde Webmail application with valid credentials
2. A crafted request containing malicious class name input is submitted to the vulnerable endpoint
3. The application uses the attacker-controlled input to instantiate a driver class
4. This reflection injection leads to arbitrary PHP object deserialization
5. Through carefully crafted serialized objects (gadget chains), the attacker achieves code execution

The vulnerability can be triggered via specially crafted email content, making it particularly dangerous as simply viewing a malicious email could initiate the attack. For detailed technical analysis of the exploitation mechanism, see the SonarSource RCE Analysis.

Detection Methods for CVE-2022-30287

Indicators of Compromise

• Unusual PHP deserialization errors or warnings in application logs
• Web requests containing serialized PHP object data in unexpected parameters
• Unexpected class instantiation attempts logged by PHP error handlers
• Anomalous outbound network connections from the web server process

Detection Strategies

• Monitor web application logs for requests containing PHP serialized data patterns (strings starting with O:, a:, or s:)
• Deploy web application firewall (WAF) rules to detect and block PHP object injection payloads
• Implement application-level logging to track class instantiation events
• Review Horde Webmail access logs for suspicious activity patterns from authenticated users

Monitoring Recommendations

• Enable detailed PHP error logging to capture deserialization warnings
• Configure intrusion detection systems to alert on PHP object injection patterns
• Monitor process execution anomalies on systems running Horde Webmail
• Implement file integrity monitoring on Horde Webmail installation directories

How to Mitigate CVE-2022-30287

Immediate Actions Required

• Update Horde Groupware Webmail Edition to the latest patched version immediately
• Review application access logs for evidence of exploitation attempts
• Restrict access to the Horde Webmail application to trusted networks if possible
• Consider temporarily disabling the affected functionality until patches can be applied

Patch Information

Security updates have been released through official channels. Debian users should apply the security updates referenced in the Debian LTS Security Announcement and the more recent Debian LTS Security Update. For the latest Horde Webmail releases, visit the official Horde Webmail application page.

SentinelOne Singularity provides automated detection and response capabilities for exploitation attempts targeting CVE-2022-30287. The platform's behavioral AI can identify and block malicious activities resulting from successful exploitation, including unauthorized code execution and lateral movement attempts.

Workarounds

• Implement strict input validation on all parameters used for class selection
• Deploy a web application firewall with rules specifically targeting PHP object injection
• Limit user privileges within the Horde Webmail application to reduce attack surface
• Isolate the Horde Webmail server in a network segment with restricted egress filtering