Techniques
Sample rules
Windows Possible Credential Dumping
- source: splunk
- technicques:
- T1003.001
- T1003
Description
The following analytic is an enhanced version of two previous analytics that identifies common GrantedAccess permission requests and CallTrace DLLs in order to detect credential dumping. GrantedAccess is the requested permissions by the SourceImage into the TargetImage.
CallTrace Stack trace of where open process is called. Included is the DLL and the relative virtual address of the functions in the call stack right before the open process call. dbgcore.dll or dbghelp.dll are two core Windows debug DLLs that have minidump functions which provide a way for applications to produce crashdump files that contain a useful subset of the entire process context. The idea behind using ntdll.dll is to blend in by using native api of ntdll.dll. For example in sekurlsa module there are many ntdll exported api, like RtlCopyMemory, used to execute this module which is related to lsass dumping.
Detection logic
`sysmon` EventCode=10 TargetImage=*\\lsass.exe granted_access IN ("0x01000", "0x1010", "0x1038", "0x40", "0x1400", "0x1fffff", "0x1410", "0x143a", "0x1438", "0x1000") CallTrace IN ("*dbgcore.dll*", "*dbghelp.dll*", "*ntdll.dll*", "*kernelbase.dll*", "*kernel32.dll*") NOT SourceUser IN ("NT AUTHORITY\\SYSTEM", "NT AUTHORITY\\NETWORK SERVICE")
| stats count min(_time) as firstTime max(_time) as lastTime by dest, SourceImage, GrantedAccess, TargetImage, SourceProcessId, SourceUser, TargetUser
| rename SourceUser as user
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_possible_credential_dumping_filter`