Query: alert when Detects attempts of decoding a base64 Gzip archive in a PowerShell script. This technique is often used as a method to l
Matching passage: Sigma rule: Detects attempts of decoding a base64 Gzip archive in a PowerShell script. This technique is often used as a method to l. Logsource: windows / ps_script. Rule: title: Suspicious FromBase64String Usage On Gzip Archive - Ps Script id: df69cb1d-b891-4cd9-90c7-d617d90100ce related: - id: d75d6b6b-adb9-48f7-824b-ac2e786efe1f type: similar status: test description: Detects attempts of decoding a base64 Gzip archive in a PowerShell script. This technique is often used as a method to load malicious content into memory afterward. references: - https://speakerdeck.com/heirhabarov/hunting-for-powershell-abuse?slide=43 author: frack113 date: 2022-12-23 tags: - attack.command-and-control - attack.t1132.001 logsource: product: windows category: ps_script definition: 'Requirements: Script Block Logging must be enabled' detection: selection: ScriptBlockText|contains|all: - FromBase64String - MemoryStream - H4sI condition: selection falsepositives: - Legitimate administrative script level: medium
Near-miss passage: Sigma rule: Detects the download of suspicious file type from a well-known file and paste sharing domain. Logsource: windows / create_stream_hash. Rule: title: Suspicious File Download From File Sharing Websites - File Stream id: 52182dfb-afb7-41db-b4bc-5336cb29b464 related: - id: ae02ed70-11aa-4a22-b397-c0d0e8f6ea99 type: similar - id: 8b48ad89-10d8-4382-a546-50588c410f0d type: similar - id: d635249d-86b5-4dad-a8c7-d7272b788586 type: similar - id: e0f8ab85-0ac9-423b-a73a-81b3c7b1aa97 type: similar - id: 7b434893-c57d-4f41-908d-6a17bf1ae98f type: similar - id: 8518ed3d-f7c9-4601-a26c-f361a4256a0c type: similar - id: 42a5f1e7-9603-4f6d-97ae-3f37d130d794 type: similar - id: 56454143-524f-49fb-b1c6-3fb8b1ad41fb type: similar - id: b6e04788-29e1-4557-bb14-77f761848ab8 type: similar - id: a0d7e4d2-bede-4141-8896-bc6e237e977c type: similar - id: 297ae038-edc2-4b2e-bb3e-7c5fc94dd5c7 type: similar status: test description: Detects the download of suspicious file type from a well-known file and paste sharing domain references: - https://www.ultimatewindowssecurity.com/securitylog/encyclopedia/event.aspx?eventid=90015 - https://www.cisa.gov/uscert/ncas/alerts/aa22-321a - https://fabian-voith.de/2020/06/25/sysmon-v11-1-reads-alternate-data-streams/ - 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/ author: Florian Roth (Nextron Systems) date: 2022-08-24 modified: 2026-03-29 tags: - attack.stealth - attack.s0139 - attack.t1564.004 logsource: product: windows category: create_stream_hash detection: selection_domain: Contents|contains: - .githubusercontent.com - 0x0.st - anonfiles.com - bashupload.com - cdn.discordapp.com - chunk.io - ddns.net - dl.dropboxusercontent.com - ghostbin.co - github.com - glitch.me - gofile.io - hastebin.com - mediafire.com - mega.nz - onrender.com - pages.dev - paste.ee - pastebin.com - pastebin.pl - pastetext.net - pixeldrain.com - privatlab.com - privatlab.net - send.exploit.in - sendspace.com - storage.googleapis.com - storjshare.io - supabase.co - temp.sh - transfer.sh - trycloudflare.com - ufile.io - w3spaces.com - workers.dev - x0.at selection_extension: TargetFilename|contains: - .cpl:Zone - .dll:Zone - .exe:Zone - .hta:Zone - .lnk:Zone - .one:Zone - .vbe:Zone - .vbs:Zone - .xll:Zone condition: all of selection_* falsepositives: - Some false positives might occur with binaries download via Github level: high