Description
'Malware authors will sometimes hardcode user agent string values when writing the network communication component of their malware. Malformed user agents can be an indication of such malware.'
- Type de règle
- Scheduled
- Version
- 1.0.6
- Fréquence
- 1d
- Période analysée
- 1d
- Déclenchement
- gt 0
Couverture MITRE déclarée
Sources déclarées
Métadonnées du fichier source. Aucune dépendance déduite du KQL.
Connecteurs
Types de données
Requête KQL
Requête originale, sans modification.
(union isfuzzy=true
(OfficeActivity | where UserAgent != ""),
(OfficeActivity
| where RecordType in ("AzureActiveDirectory", "AzureActiveDirectoryStsLogon")
| extend OperationName = Operation
| parse ExtendedProperties with * 'User-Agent\\":\\"' UserAgent2 '\\' *
| parse ExtendedProperties with * 'UserAgent", "Value": "' UserAgent1 '"' *
| where isnotempty(UserAgent1) or isnotempty(UserAgent2)
| extend UserAgent = iff( RecordType == 'AzureActiveDirectoryStsLogon', UserAgent1, UserAgent2)
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent, SourceIP = ClientIP, Account = UserId, Type, RecordType, Operation
),
(AzureDiagnostics
| where ResourceType =~ "APPLICATIONGATEWAYS"
| where OperationName =~ "ApplicationGatewayAccess"
| extend ClientIP = columnifexists("clientIP_s", "None"), UserAgent = columnifexists("userAgent_s", "None")
| where UserAgent != '-'
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent, SourceIP = ClientIP, requestUri_s, httpMethod_s, host_s, requestQuery_s, Type
),
(
W3CIISLog
| where isnotempty(csUserAgent)
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent = csUserAgent, SourceIP = cIP, Account = csUserName, Type, sSiteName, csMethod, csUriStem
),
(
AWSCloudTrail
| where isnotempty(UserAgent)
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent, SourceIP = SourceIpAddress, Account = UserIdentityUserName, Type, EventSource, EventName
),
(SigninLogs
| where isnotempty(UserAgent)
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent, SourceIP = IPAddress, Account = UserPrincipalName, Type, OperationName, tostring(LocationDetails), tostring(DeviceDetail), AppDisplayName, ClientAppUsed
),
(AADNonInteractiveUserSignInLogs
| where isnotempty(UserAgent)
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent, SourceIP = IPAddress, Account = UserPrincipalName, Type, OperationName, tostring(LocationDetails), tostring(DeviceDetail), AppDisplayName, ClientAppUsed
)
)
// Likely artefact of hardcoding
| where UserAgent startswith "User" or UserAgent startswith '\"'
// Incorrect casing
or (UserAgent startswith "Mozilla" and not(UserAgent contains_cs "Mozilla"))
// Incorrect casing
or UserAgent contains_cs "(Compatible;"
// Missing MSIE version
or UserAgent matches regex @"MSIE\s?;"
// Incorrect spacing around MSIE version
or UserAgent matches regex @"MSIE(?:\d|.{1,5}?\d\s;)"
| extend AccountName = split(Account, "@")[0], UPNSuffix = split(Account, "@")[1]
Entités déclarées
Contenus associés
Liens établis à partir des identifiants déclarés et des manifests des solutions.
Traçabilité de la source
GitHubLes valeurs affichées proviennent des fichiers du dépôt Azure/Azure-Sentinel. Elles décrivent le modèle publié, pas la configuration de votre workspace.
- Commit
7ca9800↗- Identifiant source
a357535e-f722-4afe-b375-cff362b2b376
Autres fichiers source 1
Detections/MultipleDataSources/MalformedUserAgents.yamlsource ↗GSTEP / SUIVI DU CATALOGUE
Ajouté au catalogue : 16 sept. 2026 · 05:49 UTC
Dernier changement observé : 16 sept. 2026 · 05:49 UTC