Dev-0228 File Path Hashes November 2021 (ASIM Version)

Hunt Hypothesis

‘This hunting query looks for file paths/hashes related to observed activity by Dev-0228. The actor is known to use custom version of popular tool like PsExec, Procdump etc. to carry its activity. Th

KQL Query

let files1 = dynamic(["C:\\Windows\\TAPI\\lsa.exe", "C:\\Windows\\TAPI\\pa.exe", "C:\\Windows\\TAPI\\pc.exe", "C:\\Windows\\TAPI\\Rar.exe"]);
let files2 = dynamic(["svchost.exe","wdmsvc.exe"]);
let FileHash1 = dynamic(["43109fbe8b752f7a9076eaafa417d9ae5c6e827cd5374b866672263fdebd5ec3", "ab50d8d707b97712178a92bbac74ccc2a5699eb41c17aa77f713ff3e568dcedb", "010e32be0f86545e116a8bc3381a8428933eb8789f32c261c81fd5e7857d4a77",     "56cd102b9fc7f3523dad01d632525ff673259dbc9a091be0feff333c931574f7"]);
let FileHash2 = dynamic(["2a1044e9e6e87a032f80c6d9ea6ae61bbbb053c0a21b186ecb3b812b49eb03b7", "9ab7e99ed84f94a7b6409b87e56dc6e1143b05034a5e4455e8c555dbbcd0d2dd", "18a072ccfab239e140d8f682e2874e8ff19d94311fc8bb9564043d3e0deda54b"]);
imProcessCreate
| where ((Process has_any (files1)) and (ActingProcessSHA256 has_any (FileHash1))) or ((Process has_any (files2)) and (ActingProcessSHA256 has_any (FileHash2)))
// Increase risk score if recent alerts for the host
| join kind=leftouter (
  SecurityAlert
  | where ProviderName =~ "MDATP"
  | extend ThreatName = tostring(parse_json(ExtendedProperties).ThreatName)
  | mv-expand todynamic(Entities)
  | extend DvcId = tostring(parse_json(Entities).MdatpDeviceId)
  | where isnotempty(DvcId)
  // Higher risk score are for Defender alerts related to threat actor
  | extend AlertRiskScore = iif(ThreatName has_any ("Backdoor:MSIL/ShellClient.A", "Backdoor:MSIL/ShellClient.A!dll", "Trojan:MSIL/Mimikatz.BA!MTB"), 1.0, 0.5)
  | project DvcId, AlertRiskScore) 
  on DvcId
| extend AlertRiskScore = iif(isempty(AlertRiskScore), 0.0, AlertRiskScore)
| extend AccountName = tostring(split(ActorUsername, @'\')[1]), AccountNTDomain = tostring(split(ActorUsername, @'\')[0])
| extend HostName = tostring(split(Dvc, ".")[0]), DomainIndex = toint(indexof(Dvc, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(Dvc, DomainIndex + 1), Dvc)
| project-away DomainIndex

Analytic Rule Definition

id: 29a29e5d-354e-4f5e-8321-8b39d25047bf
name: Dev-0228 File Path Hashes November 2021 (ASIM Version)
description: |
   'This hunting query looks for file paths/hashes related to observed activity by Dev-0228. The actor is known to use custom version of popular tool like PsExec, Procdump etc. to carry its activity.
    The risk score associated with each result is based on a number of factors, hosts with higher risk events should be investigated first.
    This query uses the Microsoft Sentinel Information Model - https://docs.microsoft.com/azure/sentinel/normalization'
severity: High
requiredDataConnectors: []
queryFrequency: 6h
queryPeriod: 6h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - CredentialAccess
  - Execution
relevantTechniques:
  - T1569
  - T1003
query: | 
  let files1 = dynamic(["C:\\Windows\\TAPI\\lsa.exe", "C:\\Windows\\TAPI\\pa.exe", "C:\\Windows\\TAPI\\pc.exe", "C:\\Windows\\TAPI\\Rar.exe"]);
  let files2 = dynamic(["svchost.exe","wdmsvc.exe"]);
  let FileHash1 = dynamic(["43109fbe8b752f7a9076eaafa417d9ae5c6e827cd5374b866672263fdebd5ec3", "ab50d8d707b97712178a92bbac74ccc2a5699eb41c17aa77f713ff3e568dcedb", "010e32be0f86545e116a8bc3381a8428933eb8789f32c261c81fd5e7857d4a77",     "56cd102b9fc7f3523dad01d632525ff673259dbc9a091be0feff333c931574f7"]);
  let FileHash2 = dynamic(["2a1044e9e6e87a032f80c6d9ea6ae61bbbb053c0a21b186ecb3b812b49eb03b7", "9ab7e99ed84f94a7b6409b87e56dc6e1143b05034a5e4455e8c555dbbcd0d2dd", "18a072ccfab239e140d8f682e2874e8ff19d94311fc8bb9564043d3e0deda54b"]);
  imProcessCreate
  | where ((Process has_any (files1)) and (ActingProcessSHA256 has_any (FileHash1))) or ((Process has_any (files2)) and (ActingProcessSHA256 has_any (FileHash2)))
  // Increase risk score if recent alerts for the host
  | join kind=leftouter (
    SecurityAlert
    | where ProviderName =~ "MDATP"
    | extend ThreatName = tostring(parse_json(ExtendedProperties).ThreatName)
    | mv-expand todynamic(Entities)
    | extend DvcId = tostring(parse_json(Entities).MdatpDeviceId)
    | where isnotempty(DvcId)
    // Higher risk score are for Defender alerts related to threat actor
    | extend AlertRiskScore = iif(ThreatName has_any ("Backdoor:MSIL/ShellClient.A", "Backdoor:MSIL/ShellClient.A!dll", "Trojan:MSIL/Mimikatz.BA!MTB"), 1.0, 0.5)
    | project DvcId, AlertRiskScore) 
    on DvcId
  | extend AlertRiskScore = iif(isempty(AlertRiskScore), 0.0, AlertRiskScore)
  | extend AccountName = tostring(split(ActorUsername, @'\')[1]), AccountNTDomain = tostring(split(ActorUsername, @'\')[0])
  | extend HostName = tostring(split(Dvc, ".")[0]), DomainIndex = toint(indexof(Dvc, '.'))
  | extend HostNameDomain = iff(DomainIndex != -1, substring(Dvc, DomainIndex + 1), Dvc)
  | project-away DomainIndex
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: ActorUsername
      - identifier: Name
        columnName: AccountName
      - identifier: NTDomain
        columnName: AccountNTDomain
  - entit

Required Data Sources

MITRE ATT&CK Context

• Tactic: CredentialAccess
• Tactic: Execution
• Tactic: Credential Access
• Technique: T1569 — System Services

  Adversaries may abuse system services or daemons to execute commands or programs. Adversaries can execute malicious content by interacting with or creating services either locally or remotely. Many se

• Technique: T1003 — OS Credential Dumping

  Adversaries may attempt to dump credentials to obtain account login and credential material, normally in the form of a hash or a clear text password. Credentials can be obtained from OS caches, memory

Validation (Atomic Red Team)

• T1003 — OS Credential Dumping

References

• Source Query