Sigma rule: Outlook Task/Note Reminder Received

Rule

Title

Outlook Task/Note Reminder Received

Status

test

Level

low

Author

Nasreddine Bencherchali (Nextron Systems)

Date

2023-04-05

Modified

2023-08-17

File

rules-emerging-threats/2023/Exploits/CVE-2023-23397/registry_set_exploit_cve_2023_23397_outlook_reminder_trigger.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects changes to the registry values related to outlook that indicates that a reminder was triggered for a Note or Task item. This could be a sign of exploitation of CVE-2023-23397. Further investigation is required to determine the success of an exploitation.

Log source

product

windows

category

registry_set

Detection

selection:
    TargetObject|contains|all:
        - '\SOFTWARE\Microsoft\Office\'
        - '\Outlook\'
    TargetObject|contains:
        - '\Tasks\'
        - '\Notes\'
condition: selection

False positives (as the rule lists them)

• Legitimate reminders received for a task or a note will also trigger this rule.

Tags

• attack.persistence
• attack.t1137
• cve.2023-23397
• detection.emerging-threats

CVEs this rule names

• CVE-2023-23397

MITRE ATT&CK ids this rule names

• T1137

References

• https://www.microsoft.com/en-us/security/blog/2023/03/24/guidance-for-investigating-attacks-using-cve-2023-23397/

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-emerging-threats/2023/Exploits/CVE-2023-23397/registry_set_exploit_cve_2023_23397_outlook_reminder_trigger.yml