Techniques
Sample rules
Windows Handle Duplication in Known UAC-Bypass Binaries
- source: splunk
- technicques:
- T1134.001
Description
The following analytic detects suspicious handle duplication activity targeting known Windows utilities such as ComputerDefaults.exe, Eventvwr.exe, and others. This technique is commonly used to escalate privileges or bypass UAC by inheriting or injecting elevated tokens or handles. The detection focuses on non-standard use of DuplicateHandle or token duplication where process, thread, or token handles are copied into the context of trusted, signed utilities. Such behavior may indicate attempts to execute with elevated rights without user consent. Alerts enable rapid triage using process trees, handle data, token attributes, command-lines, and binary hashes.
Detection logic
`sysmon` EventCode=10 TargetImage IN("*\\ComputerDefaults.exe", "*\\eventvwr.exe*", "*\\fodhelper.exe","*\\slui.exe","*\\sdclt.exe","*\\mmc.exe", "*\\colorcpl.exe","*\\wsreset.exe","*\\esentutl.exe", "*\PkgMgr.exe") AND NOT (SourceImage IN ("*C:\\Windows\\system32\\*","*C:\\Windows\\syswow64\\*","*C:\\Program Files\\*", "*C:\\Program Files (x86)\\*","%systemroot%\\*"))
| eval g_access_decimal = tonumber(replace(GrantedAccess,"0x",""),16)
| eval PROCESS_DUP_HANDLE = 64
| eval dup_handle_set = bit_and (g_access_decimal, PROCESS_DUP_HANDLE)
| where dup_handle_set == PROCESS_DUP_HANDLE
| stats count min(_time) as firstTime max(_time) as lastTime by SourceImage TargetImage GrantedAccess PROCESS_DUP_HANDLE g_access_decimal dup_handle_set Guid Opcode ProcessID SecurityID SourceProcessGUID SourceProcessId TargetProcessGUID TargetProcessId UserID dest granted_access parent_process_exec parent_process_guid parent_process_id parent_process_name parent_process_path process_exec process_guid process_id process_name process_path signature signature_id user_id vendor_product CallTrace EventID
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_handle_duplication_in_known_uac_bypass_binaries_filter`