Detect RoundCube Webmail Deserialization of Untrusted Data (CVE-2025-49113) in Sumo Logic CSE
CVE-2025-49113 is an actively exploited deserialization of untrusted data vulnerability (CWE-502) in Roundcube Webmail. When exploited, an attacker can send a specially crafted serialized PHP object via the web interface, leading to remote code execution on the underlying server. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog and requires immediate patching to versions 1.5.10 or 1.6.11.
MITRE ATT&CK
- Tactic
- Initial Access Execution Persistence
Sumo Detection Query
_sourceCategory=web/access OR _sourceCategory=proxy OR _sourceCategory=waf
| parse regex "(?<src_ip>\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}) .* \"(?<method>GET|POST|PUT|PATCH) (?<uri>\\S+) HTTP" nodrop
| where uri matches "*roundcube*" or uri matches "*/index.php*"
| where uri matches "*O%3A*" or uri matches "*a%3A*" or uri matches "*s%3A*"
OR _raw matches "O:[0-9]+:\\"" OR _raw matches "a:[0-9]+:{"
| eval deserialization_payload = if(uri matches "*O%3A*" OR uri matches "*a%3A*", "url_encoded", "body_encoded")
| count as hit_count, values(uri) as request_uris by src_ip, method, deserialization_payload
| where hit_count >= 1
| sort by hit_count descSumo Logic query detecting PHP deserialization payloads (URL-encoded or raw) in HTTP requests to Roundcube Webmail, useful for identifying CVE-2025-49113 exploitation attempts across web and proxy log sources.
Data Sources
Required Tables
False Positives & Tuning
- Roundcube installations with custom plugins that pass serialized objects in URL parameters
- Automated test suites validating Roundcube form submission behaviors
- Security scanners configured to test for deserialization vulnerabilities
- Load balancer health checks that include encoded payloads in synthetic requests
Other platforms for CVE-2025-49113
Testing Methodology
Validate this detection against 4 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Roundcube Deserialization Probe via GET Parameter
Expected signal: HTTP GET request to Roundcube /index.php with O%3A in query string captured in web access logs; PHP error log may show unserialize() invocation
- Test 2Roundcube POST Body Deserialization with Crafted Object
Expected signal: POST request to Roundcube /index.php with serialized object in body captured by WAF or proxy; PHP error log records unserialize call or type error
- Test 3Web Shell Drop via Simulated Roundcube RCE
Expected signal: File creation event in Roundcube web root (inotify/auditd/EDR file write event); new .php file with non-standard name in web root directory
- Test 4Outbound Reverse Shell from PHP Process (Post-Exploitation Simulation)
Expected signal: Process creation event: www-data spawning bash with /dev/tcp redirect; outbound TCP connection from web server worker to port 4444; EDR network connection alert for web process initiating outbound shell
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