Techniques › T1534
T1534 Internal Spearphishing
lateral movement — Linux, macOS, Office Suite, SaaS, Windows · attack.mitre.org · JSON
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MITRE detection strategy
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analytics
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Sigma rules tagged attack.t1534
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KEV CVEs mapped here
<p>After they already have access to accounts or systems within the environment, adversaries may use internal spearphishing to gain access to additional information or compromise other users within the same organization. Internal spearphishing is multi-staged campaign where a legitimate account is initially compromised either by controlling the user's device or by compromising the account credentials of the user. Adversaries may then attempt to take advantage of the trusted internal account to increase the likelihood of tricking more victims into falling for phish attempts, often incorporating Impersonation.</p><p>For example, adversaries may leverage Spearphishing Attachment or Spearphishing Link as part of internal spearphishing to deliver a payload or redirect to an external site to capture credentials through Input Capture on sites that mimic login interfaces.</p><p>Adversaries may also leverage internal chat apps, such as Microsoft Teams, to spread malicious content or engage users in attempts to capture sensitive information and/or credentials.</p>
KEV CVEs mapped to this technique · CTID Mappings Explorer
None. No KEV entry in the public mapping names this technique. Given that 74.7% of KEV has no mapping at all, this says more about the mapping than about the technique.
Detection strategy · ATT&CK Enterprise v19.2
- DET0054 Internal Spearphishing via Trusted Accounts v1.0
AN0147 WindowsSequence of internal email sent from a recently compromised user account (preceded by abnormal logon or device activity), with attachments or links leading to execution or credential harvesting. Defender observes: internal mail delivery to peers with high entropy attachments, followed by click events, process initiation, or credential prompts.m365:unified
SendOnBehalf, MessageSend, ClickThrough, MailItemsAccessed→ DC0038 Application Log ContentTunable:TimeWindowUserContextAttachmentEntropyThresholdAN0148 LinuxDelivery of suspicious internal communication (e.g., Thunderbird, Evolution) using compromised internal accounts. Sequence of: unexpected user activity + mail transfer logs + download or execution of attachments.Application:Mailsmtpd$.*$: .*from=[.*@internaldomain.com](mailto:.*@internaldomain.com) to=[.*@internaldomain.com](mailto:.*@internaldomain.com)→ DC0038 Application Log ContentTunable:SubjectLineAnomalyAttachmentTypeAN0149 macOSAbnormal Apple Mail use, including internal email relays followed by file execution or script events (e.g., attachments launched via Preview, terminal triggered from Mail.app)Tunable:ExecutionChainDepthMailScriptFlagAN0150 SaaSInternal spearphishing via SaaS applications (e.g., Slack, Teams, Gmail): message sent from compromised user with attachment or URL, followed by click and credential access behavior.Tunable:UserAnomalyThresholdFileRiskScoringAN0151 Office SuiteOutlook or Word used to forward suspicious internal attachments with macro content. Defender observes attachment forwarding, auto-opening behaviors, or macro prompt interactions.Tunable:MacroExecutionWindowAttachmentNameHeuristics
Sigma rules · SigmaHQ da9bb07d64, tag attack.t1534
No Sigma rule carries this tag. MITRE publishes a detection strategy above, so the behaviour is specified; what is missing is public detection content.