Sigma Rules
13 rules found for "@neu5ron"
MITRE BZAR Indicators for Execution
Windows DCE-RPC functions which indicate an execution techniques on the remote system. All credit for the Zeek mapping of the suspicious endpoint/operation field goes to MITRE
MITRE BZAR Indicators for Persistence
Windows DCE-RPC functions which indicate a persistence techniques on the remote system. All credit for the Zeek mapping of the suspicious endpoint/operation field goes to MITRE.
Potential PetitPotam Attack Via EFS RPC Calls
Detects usage of the windows RPC library Encrypting File System Remote Protocol (MS-EFSRPC). Variations of this RPC are used within the attack refereed to as PetitPotam. The usage of this RPC function should be rare if ever used at all. Thus usage of this function is uncommon enough that any usage of this RPC function should warrant further investigation to determine if it is legitimate. View surrounding logs (within a few minutes before and after) from the Source IP to. Logs from from the Source IP would include dce_rpc, smb_mapping, smb_files, rdp, ntlm, kerberos, etc..'
Suspicious DNS Z Flag Bit Set
The DNS Z flag is bit within the DNS protocol header that is, per the IETF design, meant to be used reserved (unused). Although recently it has been used in DNSSec, the value being set to anything other than 0 should be rare. Otherwise if it is set to non 0 and DNSSec is being used, then excluding the legitimate domains is low effort and high reward. Determine if multiple of these files were accessed in a short period of time to further enhance the possibility of seeing if this was a one off or the possibility of larger sensitive file gathering. This Sigma query is designed to accompany the Corelight Threat Hunting Guide, which can be found here: https://www3.corelight.com/corelights-introductory-guide-to-threat-hunting-with-zeek-bro-logs'
Transferring Files with Credential Data via Network Shares - Zeek
Transferring files with well-known filenames (sensitive files with credential data) using network shares
Enabled User Right in AD to Control User Objects
Detects scenario where if a user is assigned the SeEnableDelegationPrivilege right in Active Directory it would allow control of other AD user objects.
Active Directory User Backdoors
Detects scenarios where one can control another users or computers account without having to use their credentials.
Weak Encryption Enabled and Kerberoast
Detects scenario where weak encryption is enabled for a user profile which could be used for hash/password cracking.
Windows Event Auditing Disabled
Detects scenarios where system auditing (i.e.: Windows event log auditing) is disabled. This may be used in a scenario where an entity would want to bypass local logging to evade detection when Windows event logging is enabled and reviewed. Also, it is recommended to turn off "Local Group Policy Object Processing" via GPO, which will make sure that Active Directory GPOs take precedence over local/edited computer policies via something such as "gpedit.msc". Please note, that disabling "Local Group Policy Object Processing" may cause an issue in scenarios of one off specific GPO modifications - however, it is recommended to perform these modifications in Active Directory anyways.
Unauthorized System Time Modification
Detect scenarios where a potentially unauthorized application or user is modifying the system time.
Potential Ransomware or Unauthorized MBR Tampering Via Bcdedit.EXE
Detects potential malicious and unauthorized usage of bcdedit.exe
ETW Trace Evasion Activity
Detects command line activity that tries to clear or disable any ETW trace log which could be a sign of logging evasion.
OMIGOD HTTP No Authentication RCE - CVE-2021-38647
Detects the exploitation of OMIGOD (CVE-2021-38647) which allows remote execute (RCE) commands as root with just a single unauthenticated HTTP request. Verify, successful, exploitation by viewing the HTTP client (request) body to see what was passed to the server (using PCAP). Within the client body is where the code execution would occur. Additionally, check the endpoint logs to see if suspicious commands or activity occurred within the timeframe of this HTTP request.