CVE-2022-30287 Overview
CVE-2022-30287 affects Horde Groupware Webmail Edition through version 5.2.22. The vulnerability allows an authenticated attacker to perform a reflection injection attack that instantiates an arbitrary driver class. This primitive leads to unsafe deserialization of PHP objects, which can result in remote code execution on the webmail server. The flaw is tracked under CWE-470: Use of Externally-Controlled Input to Select Classes or Code (Unsafe Reflection).
Critical Impact
Authenticated attackers can chain unsafe reflection with PHP object deserialization to execute arbitrary code in the context of the Horde webmail application.
Affected Products
- Horde Groupware Webmail Edition through 5.2.22
- Debian Linux 10 (buster) packages of Horde
- Horde installations distributed via Debian LTS
Discovery Timeline
- 2022-07-28 - CVE-2022-30287 published to the National Vulnerability Database (NVD)
- 2022-08 - Debian LTS publishes advisory for affected Horde packages
- 2024-10 - Additional Debian LTS announcement references the issue
- 2024-11-21 - Last updated in the NVD database
Technical Details for CVE-2022-30287
Vulnerability Analysis
The vulnerability stems from how Horde Groupware resolves driver class names from user-controlled input. An attacker who can reach an authenticated endpoint can supply a class identifier that Horde uses to instantiate an arbitrary PHP class through reflection. Once an attacker controls which class is instantiated, the application path leads into PHP object deserialization with untrusted data.
The combination of unsafe reflection and deserialization is the classic precondition for a PHP object injection chain. By selecting a class whose __wakeup, __destruct, or other magic methods perform sensitive operations, an attacker can trigger filesystem writes, command execution, or further gadget chains. Public technical analysis by SonarSource describes the full chain from email-borne input to remote code execution in the SonarSource RCE analysis.
Root Cause
The root cause is improper validation of class identifiers passed into a driver-loading routine. Horde trusts the supplied string and uses it to instantiate a class without restricting the candidate set to an allowlist. PHP then unserializes attacker-influenced data within that class context, producing the object injection primitive.
Attack Vector
Exploitation is network-based and requires low-privilege authentication and user interaction. An attacker submits a crafted request to a vulnerable Horde endpoint, selecting a driver class that triggers deserialization of attacker-controlled serialized data. Successful exploitation yields code execution under the webmail process account, exposing mailboxes, credentials, and stored attachments.
No verified public exploit code is available; the vulnerability mechanism is described in prose per the referenced advisories. See the Debian LTS announcement for package-level details.
Detection Methods for CVE-2022-30287
Indicators of Compromise
- Unexpected PHP processes spawning shell interpreters (sh, bash, /bin/sh -c) under the Horde or web server account
- New or modified files in Horde application directories, particularly under config/ and tmp/ paths
- HTTP requests to Horde endpoints containing serialized PHP payloads (strings beginning with O: or a: followed by class names)
- Outbound network connections from the webmail host to attacker-controlled infrastructure shortly after authenticated sessions
Detection Strategies
- Inspect web server access logs for POST requests to Horde driver-loading endpoints with anomalous class name parameters
- Alert on PHP serialized object markers in request bodies or query parameters destined for Horde
- Monitor for child processes of php-fpm or Apache that are not part of normal Horde operation
Monitoring Recommendations
- Forward Apache, Nginx, and PHP-FPM logs to a central analytics platform and retain at least 90 days of history
- Baseline normal Horde HTTP request patterns and parameter values to surface deviations
- Monitor file integrity on Horde installation directories and configuration paths
How to Mitigate CVE-2022-30287
Immediate Actions Required
- Upgrade Horde Groupware Webmail Edition beyond version 5.2.22 using packages from the vendor or the Debian security archive
- Restrict Horde administrative and webmail endpoints to trusted networks or VPN access while patching
- Rotate credentials, session tokens, and any secrets stored on the webmail host after confirming clean state
- Review web server logs for past exploitation attempts targeting driver class parameters
Patch Information
Debian and downstream maintainers released fixed Horde packages tracked in the August 2022 Debian LTS announcement and the October 2024 Debian LTS announcement. Refer to the Horde Webmail product page for upstream release information.
Workarounds
- Disable affected Horde modules if patching cannot be performed immediately
- Enforce strict authentication and limit account creation to reduce the pool of users able to reach the vulnerable code path
- Place a web application firewall in front of Horde with rules that block PHP serialized payload patterns in request parameters
# Example WAF/log monitoring pattern to flag PHP serialized payloads in Horde requests
grep -E 'O:[0-9]+:"[A-Za-z_\\]+":[0-9]+:\{' /var/log/apache2/horde_access.log
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
