Detect SolarWinds Web Help Desk Deserialization of Untrusted Data (CVE-2025-26399) in CrowdStrike LogScale
CVE-2025-26399 is a deserialization of untrusted data vulnerability (CWE-502) in SolarWinds Web Help Desk. Exploitation allows remote attackers to execute arbitrary code by sending maliciously crafted serialized Java objects to the application. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild. SolarWinds Web Help Desk is widely deployed in enterprise and government environments for IT service management, making this a high-priority target for threat actors seeking privileged network access.
MITRE ATT&CK
- Tactic
- Initial Access Execution Persistence
LogScale Detection Query
event_simpleName IN ("ProcessRollup2", "SyntheticProcessRollup2")
| ParentBaseFileName = "java.exe"
| FileName IN ("cmd.exe", "powershell.exe", "wscript.exe", "cscript.exe", "mshta.exe", "certutil.exe", "bitsadmin.exe", "curl.exe", "wget.exe")
| ParentCommandLine = /(?i)(webhelpdesk|whd)/
| eval DetectionContext = "CVE-2025-26399: WHD Java spawned suspicious process"
| table timestamp, ComputerName, UserName, ParentBaseFileName, ParentCommandLine, FileName, CommandLine, SHA256HashData, DetectionContext
| sort timestamp desc
// Complement: network-based detection for reverse shell C2
// event_simpleName = "NetworkConnectIP4"
// | LocalAddressIP4 != "127.0.0.1"
// | RemotePort IN ("4444", "9001", "1337", "8888")
// | ImageFileName = /(?i)java\.exe$/
// | CommandLine = /(?i)(webhelpdesk|whd)/CrowdStrike Falcon CQL (Humio) query detecting CVE-2025-26399 exploitation by correlating WHD Java process events with suspicious child process spawns; supplemented with a commented network query for reverse shell C2 detection.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate administrative scripts triggered by WHD Java on managed endpoints with broad Java tooling
- CrowdStrike-monitored development or QA machines running Web Help Desk in test environments
- ITSM automation workflows that intentionally invoke PowerShell or cmd.exe via Java service triggers
- Vulnerability scanning agents running on the WHD host that trigger process chains resembling exploitation
Other platforms for CVE-2025-26399
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 1Simulate Java Deserialization Reverse Shell Spawn (Windows)
Expected signal: Sysmon Event ID 1: ProcessCreate with ParentImage=java.exe, Image=cmd.exe, CommandLine containing 'whoami'; DeviceProcessEvents in MDE showing same relationship
- Test 2Simulate WHD Java Process Network Beacon to C2 Port
Expected signal: Sysmon Event ID 3: NetworkConnect from java.exe to 127.0.0.1:4444; MDE DeviceNetworkEvents showing RemotePort=4444 from InitiatingProcessFileName=java.exe
- Test 3Simulate Malicious Class File Drop by WHD JVM (Linux)
Expected signal: Linux auditd or Sysmon-for-Linux: file creation event under /tmp owned by webhelpdesk user, initiated by java process; file content containing shell redirect syntax
- Test 4Reproduce Serialized Object HTTP POST to WHD Endpoint (Lab)
Expected signal: WAF/proxy logs showing HTTP POST with Content-Type: application/octet-stream and body beginning with AC ED 00 05; WHD application logs showing deserialization attempt (may log exception)
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