7-zip-prep-for-exfiltration

Description

This query was originally published in the threat analytics report, "Exchange Server zero-days exploited in the wild". In early March 2021, Microsoft released patches for four different zero-day vulnerabilities affecting Microsoft Exchange Server. The vulnerabilities were being used in a coordinated attack. For more information on the vulnerabilities, visit the following links: 1. CVE-2021-26855 2. CVE-2021-26857 3. CVE-2021-26858 4. CVE-2021-27065 The following query detects 7-zip activity associated with this threat. 7-ZIP is a legitimate tool used for file archiving; however, unusual 7-ZIP activity combined with other evidence might indicate that an attacker is compressing data for exfiltration. More queries related to this threat can be found under the See also section of this page. Reference - https://msrc-blog.microsoft.com/2021/03/02/multiple-security-updates-released-for-exchange-server/

Query · kql

DeviceProcessEvents | where FileName == "7z.exe" | where ProcessCommandLine contains "ProgramData\\pst"
Raw source 7-zip-prep-for-exfiltration · KQL
Esc
Published by Azure/Azure-Sentinel ↗, licensed under MIT ↗. Reproduced here unmodified. 
id: 66d73c14-f888-4748-a0ae-609577fcb51f
name: 7-zip-prep-for-exfiltration
description: |
  This query was originally published in the threat analytics report, "Exchange Server zero-days exploited in the wild".
  In early March 2021, Microsoft released patches for four different zero-day vulnerabilities affecting Microsoft Exchange Server. The vulnerabilities were being used in a coordinated attack. For more information on the vulnerabilities, visit the following links:
  1. CVE-2021-26855
  2. CVE-2021-26857
  3. CVE-2021-26858
  4. CVE-2021-27065
  The following query detects 7-zip activity associated with this threat. 7-ZIP is a legitimate tool used for file archiving; however, unusual 7-ZIP activity combined with other evidence might indicate that an attacker is compressing data for exfiltration.
  More queries related to this threat can be found under the See also section of this page.
  Reference - https://msrc-blog.microsoft.com/2021/03/02/multiple-security-updates-released-for-exchange-server/
requiredDataConnectors:
- connectorId: MicrosoftThreatProtection
  dataTypes:
  - DeviceProcessEvents
tactics:
- Exfiltration
query: |
  DeviceProcessEvents | where FileName == "7z.exe" | where ProcessCommandLine contains "ProgramData\\pst"

Detection rules belong to the projects that publish them and remain under their own licenses. This site indexes and links to them; it claims no rights in them.