ISO or Image Mount Indicator in Recent Files

testmedium
log source: windows · file_eventauthor Florian Roth (Nextron Systems)date 2022-02-11
01

description

What this is, in brief.

Detects the creation of recent element file that points to an .ISO, .IMG, .VHD or .VHDX file as often used in phishing attacks. This can be a false positive on server systems but on workstations users should rarely mount .iso or .img files.

02

tags

attack.initial-accessattack.t1566.001
03

rule source (YAML)

title: ISO or Image Mount Indicator in Recent Files
id: 4358e5a5-7542-4dcb-b9f3-87667371839b
status: test
description: |
    Detects the creation of recent element file that points to an .ISO, .IMG, .VHD or .VHDX file as often used in phishing attacks.
    This can be a false positive on server systems but on workstations users should rarely mount .iso or .img files.
references:
    - https://www.microsoft.com/security/blog/2021/05/27/new-sophisticated-email-based-attack-from-nobelium/
    - https://www.trendmicro.com/vinfo/us/security/news/cybercrime-and-digital-threats/malicious-spam-campaign-uses-iso-image-files-to-deliver-lokibot-and-nanocore
    - https://blog.emsisoft.com/en/32373/beware-new-wave-of-malware-spreads-via-iso-file-email-attachments/
    - https://insights.sei.cmu.edu/blog/the-dangers-of-vhd-and-vhdx-files/
author: Florian Roth (Nextron Systems)
date: 2022-02-11
tags:
    - attack.initial-access
    - attack.t1566.001
logsource:
    product: windows
    category: file_event
detection:
    selection:
        TargetFilename|endswith:
            - '.iso.lnk'
            - '.img.lnk'
            - '.vhd.lnk'
            - '.vhdx.lnk'
        TargetFilename|contains: '\Microsoft\Windows\Recent\'
    condition: selection
falsepositives:
    - Cases in which a user mounts an image file for legitimate reasons
level: medium
04

detects techniques (1)

ATT&CK techniques this enables or maps to.

05

references

External citations — patches, advisories, analysis.