Potentially Suspicious File Download From File Sharing Domain Via PowerShell.EXE
Detects potentially suspicious file downloads from file sharing domains using PowerShell.exe
Sigma rule (View on GitHub)
1title: Potentially Suspicious File Download From File Sharing Domain Via PowerShell.EXE
2id: b6e04788-29e1-4557-bb14-77f761848ab8
3status: experimental
4description: Detects potentially suspicious file downloads from file sharing domains using PowerShell.exe
5references:
6 - https://labs.withsecure.com/publications/fin7-target-veeam-servers
7 - https://github.com/WithSecureLabs/iocs/blob/344203de742bb7e68bd56618f66d34be95a9f9fc/FIN7VEEAM/iocs.csv
8 - https://www.microsoft.com/en-us/security/blog/2024/01/17/new-ttps-observed-in-mint-sandstorm-campaign-targeting-high-profile-individuals-at-universities-and-research-orgs/
9 - https://www.huntress.com/blog/slashandgrab-screen-connect-post-exploitation-in-the-wild-cve-2024-1709-cve-2024-1708
10author: Nasreddine Bencherchali (Nextron Systems)
11date: 2024-02-23
12modified: 2024-10-21
13tags:
14 - attack.execution
15logsource:
16 category: process_creation
17 product: windows
18detection:
19 selection_img:
20 - Image|endswith:
21 - '\powershell.exe'
22 - '\pwsh.exe'
23 - OriginalFileName:
24 - 'PowerShell.EXE'
25 - 'pwsh.dll'
26 selection_websites:
27 CommandLine|contains:
28 # Note: You might want to baseline the github domain before including it
29 # - '.githubusercontent.com' # Includes both gists and github repositories / Michael Haag (idea).
30 - 'anonfiles.com'
31 - 'cdn.discordapp.com'
32 - 'ddns.net'
33 - 'dl.dropboxusercontent.com'
34 - 'ghostbin.co'
35 - 'glitch.me'
36 - 'gofile.io'
37 - 'hastebin.com'
38 - 'mediafire.com'
39 - 'mega.nz'
40 - 'onrender.com'
41 - 'pages.dev'
42 - 'paste.ee'
43 - 'pastebin.com'
44 - 'pastebin.pl'
45 - 'pastetext.net'
46 - 'pixeldrain.com'
47 - 'privatlab.com'
48 - 'privatlab.net'
49 - 'send.exploit.in'
50 - 'sendspace.com'
51 - 'storage.googleapis.com'
52 - 'storjshare.io'
53 - 'supabase.co'
54 - 'temp.sh'
55 - 'transfer.sh'
56 - 'trycloudflare.com'
57 - 'ufile.io'
58 - 'w3spaces.com'
59 - 'workers.dev'
60 selection_download:
61 CommandLine|contains:
62 - '.DownloadString('
63 - '.DownloadFile('
64 - 'Invoke-WebRequest '
65 - 'iwr '
66 - 'wget '
67 condition: all of selection_*
68falsepositives:
69 - Unknown
70level: high
References
-
WithSecure Intelligence identified attacks which occurred in late March 2023 against internet-facing servers running Veeam Backup & Replication software. Our research indicates that the intrusion set used in these attacks has overlaps with those attributed to the FIN7 activity group. It is likely that initial access & execution was achieved through a recently patched Veeam Backup & Replication vulnerability, CVE-2023-27532.
Read More -
-
A distinct subset of Mint Sandstorm targets high-profile individuals working on Middle Eastern affairs at universities and research orgs.
Read More -
SlashAndGrab: ScreenConnect Post-Exploitation in the Wild (CVE-2024-1709 & CVE-2024-1708) | Huntress
Adversaries have been VERY busy in the wake of the ScreenConnect vulnerabilities (CVE-2024-1709 & CVE-2024-1708). Here’s all the post-exploitation details, tradecraft, and tactics we’ve observed so far!
Read More
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