Detect Internal Spearphishing in IBM QRadar
Adversaries who have already compromised an account or system may abuse the trusted internal identity to send phishing messages to other users within the same organization. Because the message originates from a known colleague, recipients are far more likely to open attachments, click links, or provide credentials. Campaigns typically combine a compromised mailbox or chat account with a weaponized attachment, a credential-harvesting link, or a malicious macro-enabled document. Real-world actors include Gamaredon (Outlook VBA module auto-sending phishing to contacts), Kimsuky (stolen credentials reused for internal mail), Leviathan/APT40, and HEXANE. Detection surfaces include anomalous send volume or recipient patterns from an internal account, Outlook spawning suspicious child processes (macro execution), Microsoft Teams delivering external URLs or files, and mass-BCC or reply-all abuse patterns.
MITRE ATT&CK
- Tactic
- Lateral Movement
- Technique
- T1534 Internal Spearphishing
- Canonical reference
- https://attack.mitre.org/techniques/T1534/
QRadar Detection Query
-- Signal 1: Outlook spawning suspicious child processes (Sysmon EventID 1)
SELECT
DATEFORMAT(starttime, 'YYYY-MM-dd HH:mm:ss') AS event_time,
logsourcename(logsourceid) AS log_source,
username,
"ParentImage",
"Image",
"CommandLine",
'OutlookMacroChildProcess' AS signal
FROM events
WHERE
LOGSOURCETYPENAME(devicetype) ILIKE '%Windows%'
AND QIDNAME(qid) ILIKE '%Process Create%'
AND "ParentImage" ILIKE '%\\outlook.exe'
AND (
"Image" ILIKE '%\\cmd.exe' OR
"Image" ILIKE '%\\powershell.exe' OR
"Image" ILIKE '%\\pwsh.exe' OR
"Image" ILIKE '%\\wscript.exe' OR
"Image" ILIKE '%\\cscript.exe' OR
"Image" ILIKE '%\\mshta.exe' OR
"Image" ILIKE '%\\rundll32.exe' OR
"Image" ILIKE '%\\regsvr32.exe' OR
"Image" ILIKE '%\\certutil.exe' OR
"Image" ILIKE '%\\bitsadmin.exe' OR
"Image" ILIKE '%\\curl.exe' OR
"Image" ILIKE '%\\wget.exe'
)
AND starttime > NOW() - 86400000
UNION
-- Signal 2: High-volume internal email send (O365 audit logs)
SELECT
DATEFORMAT(MIN(starttime), 'YYYY-MM-dd HH:mm:ss') AS event_time,
'O365-AuditLog' AS log_source,
username,
'O365-Send' AS "ParentImage",
CONCAT(CAST(COUNT(*) AS VARCHAR), ' emails/hr') AS "Image",
CONCAT('UniqueRecipients:', CAST(COUNT(DISTINCT destinationip) AS VARCHAR)) AS "CommandLine",
'HighVolumeInternalSend' AS signal
FROM events
WHERE
LOGSOURCETYPENAME(devicetype) ILIKE '%Office 365%'
AND QIDNAME(qid) ILIKE '%Send%'
AND username NOT ILIKE '%#EXT#%'
AND starttime > NOW() - 86400000
GROUP BY
username,
DATEFORMAT(starttime, 'YYYY-MM-dd HH')
HAVING COUNT(*) > 20
ORDER BY event_time DESCAQL query detecting internal spearphishing via two correlated signals: Sysmon process creation events where outlook.exe spawns LOLBin child processes (indicating macro execution from a phishing email), and O365 audit log patterns showing internal accounts sending more than 20 emails per hour (indicating a compromised mailbox sending mass internal phishing). Results are unified and sorted by recency.
Data Sources
Required Tables
False Positives & Tuning
- Outlook COM add-ins (e.g., DocuSign, Zoom, Teams plugin) may legitimately cause outlook.exe to spawn rundll32.exe or msiexec.exe during updates or feature initialization.
- HR or IT bulk notification campaigns (password reset notices, benefits enrollment, system maintenance alerts) sent from shared service accounts will exceed the 20-email threshold.
- Legal or compliance teams sending mass disclosure or policy acknowledgment emails from internal accounts during regulatory events may appear as high-volume senders.
Other platforms for T1534
Testing Methodology
Validate this detection against 4 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Outlook VBA Macro Auto-Send (Simulated Gamaredon Pattern)
Expected signal: Sysmon Event ID 1: powershell.exe spawned with Outlook COM object instantiation. OfficeActivity O365 log: Operation=Send from the test account. If Outlook is running, Sysmon Event ID 10 (ProcessAccess) may show PowerShell accessing the Outlook process. Exchange/O365 message trace will record the outbound message.
- Test 2Write Malicious Macro to Outlook VbaProject.OTM
Expected signal: Sysmon Event ID 11 (File Create): file creation event for the test artifact in %TEMP%. Sysmon Event ID 1: powershell.exe with path references to VbaProject.OTM. If Outlook is running and VbaProject.OTM is actually modified, Sysmon will log file modification events against the OTM path.
- Test 3Microsoft Teams Message with External Link (Simulated via Graph API)
Expected signal: O365 OfficeActivity: RecordType=MicrosoftTeams, Operation=MessageCreatedHasLink, with the external URL in ExtraProperties. Azure AD sign-in log entry for the Graph API token use. Microsoft Defender for Cloud Apps (MCAS) may generate an alert for 'Suspicious inbox forwarding' or 'Unusual file share' depending on policy.
- Test 4Simulate Compromised Account Bulk Send via PowerShell Exchange Online
Expected signal: O365 Unified Audit Log: multiple Send operations from [email protected] within a short window. Exchange message trace: batch of outbound messages with identical subject. Azure AD: interactive authentication event for the PowerShell connection. OfficeActivity table in Sentinel: Operation=Send entries for each recipient.
References (9)
- https://attack.mitre.org/techniques/T1534/
- https://blog.trendmicro.com/phishing-starts-inside/
- https://www.microsoft.com/en-us/security/blog/2023/08/02/midnight-blizzard-conducts-targeted-social-engineering-over-microsoft-teams/
- https://www.welivesecurity.com/2020/06/11/gamaredon-group-grows-its-game/
- https://www.cisa.gov/sites/default/files/publications/AA21-200A.pdf
- https://secureworks.com/research/lyceum-takes-center-stage-in-middle-east-campaign
- https://learn.microsoft.com/en-us/microsoft-365/compliance/audit-log-search-tool
- https://learn.microsoft.com/en-us/defender-office-365/anti-phishing-policies-about
- https://learn.microsoft.com/en-us/microsoftteams/teams-security-guide
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