MALICIOUS — virussign.com_caffb8df761453e2fb63631163a00050.vir
MALICIOUS — virussign.com_caffb8df761453e2fb63631163a00050.vir is a pe sample analyzed by MalwareAnalyzer by Cyble with a malicious verdict (99/100), attributed to the Fsysna family. 6 of 55 detection engines flagged it, exhibiting 5 ATT&CK techniques.
Identification
- SHA-256:
af0fae7ab9d04149fc82caf146332f2c4fb42049132a0c0b9950c43a0b3433ce - SHA-1:
b19a9e2379c0ee0375641ab0be80f8bf9b176cdc - MD5:
caffb8df761453e2fb63631163a00050 - imphash:
b6230692891661869cecd581561a21f4 - ssdeep:
12288:zW6n3sX4yCFr2ZemYOpSPIsGWeKZl4q7sioX3:zW6ncoyqOp6IsTl/mX3 - TLSH:
T1CD4CBEC87AC7DD54E8E97B86E45544BDD68BD12F186D2E8F0392C2386F812F3A871112 - Submitted as: virussign.com_caffb8df761453e2fb63631163a00050.vir
- File type: pe · Size: 533240 bytes
- Verdict: malicious (99/100) · Family: Fsysna
Source: VirusSign · first seen 2026-08-20T00:00:00.000Z · SHA-256 verified
Detections (6 of 55 engines)
- ClamAV (daily): Win.Worm.Guap-4
- YARA: delivr.to detections: DLV_Maldoc_VBA_AutoExec
- YARA: MalwareAnalyser community pack: TL_Windows_Persistence_RunKey
- Microsoft Defender: Trojan:Win32/Fsysna!pz
- Emsisoft (Emergency Kit): Gen:Heur.Spesr.VB.1
- Kaspersky (KVRT): Trojan.Win32.Fsysna.gevi
MITRE ATT&CK
Why this verdict
The malicious score of 99/100 is the fusion of 12 weighted signals:
- ClamAV (daily) flagged Win.Worm.Guap-4 (rule
Win.Worm.Guap-4) - engine signal, weight 0.90, confidence 0.95 - Memory forensics: 2 finding(s), e.g. SSDT hook (rule
windows.ssdt.SSDT) - memory signal, weight 0.50, confidence 0.85 - Observed at runtime: Windows Service (T1543.003) (rule
Windows Service) - dynamic signal, weight 0.40, confidence 0.90 - Contacted 26 external host(s) at runtime (21 HTTP) - network signal, weight 0.40, confidence 0.80
- Anti-analysis: T1497.001, T1082, T1622 - dynamic signal, weight 0.40, confidence 0.75
- Extracted BlackShades config (0 C2) - engine signal, weight 0.45, confidence 0.60
- YARA: delivr.to detections flagged DLV_Maldoc_VBA_AutoExec (rule
DLV_Maldoc_VBA_AutoExec) - engine signal, weight 0.35, confidence 0.70 - YARA: MalwareAnalyser community pack flagged TL_Windows_Persistence_RunKey (rule
TL_Windows_Persistence_RunKey) - engine signal, weight 0.35, confidence 0.70 - persist via registry run key (rule
persist via registry run key) - capa signal, weight 0.35, confidence 0.60 - communicate over HTTP (rule
communicate over HTTP) - capa signal, weight 0.30, confidence 0.60 - Dropped 2 executable file(s) at runtime - dynamic signal, weight 0.20, confidence 0.60
- Observed at runtime: Modify Registry (T1112) (rule
Modify Registry) - dynamic signal, weight 0.12, confidence 0.90
Dynamic analysis (windows)
11247 behavior events · 2 ATT&CK techniques · 3 dropped files.
Runtime network
- www.msftconnecttest.com
- rb.symcd.com
- rb.symcb.com
- inference.location.live.net
- to-do.office.com
- staging.to-do.officeppe.com
- teams.cloud.microsoft
- outlook.office.com
- outlook.office365.com
- outlook.cloud.microsoft
- ctldl.windowsupdate.com
- login.live.com
- ocsp.digicert.com
- desktop-hsgcbep
- v20.events.data.microsoft.com
- config.edge.skype.com
- windows.msn.com
- oneocsp.microsoft.com
- www.msn.com
- officeclient.microsoft.com
Dropped files
- C:\Users\analyst\AppData\Local\Temp\LOEWUDXMCIQHGRO\service.exe -
36ac7fe5b3c0e1e873a8eee883967ffb38a5bae5135f0301af78080714334c49 - C:\Users\analyst\AppData\Local\TempENYAJ.bat -
065f7c31986e5313b7afdfbe37050accd2b4d9d357f2d049b40b99a34729afff - 7ceeaed4083605a40fffa26d4a6a16fe5bbe873b887376007c15a3d569bc7442 -
7ceeaed4083605a40fffa26d4a6a16fe5bbe873b887376007c15a3d569bc7442
Embedded URLs
- http://www.msftconnecttest.com/connecttest.txt
- http://rb.symcd.com/MFEwTzBNMEswSTAJBgUrDgMCGgUABBTDRSYViRCZTxmZjLENmnwVjLly9QQU1MAGIknrOUvdk%2BJcobhHdglyA1gCEF0QyxjrOnkAh4OrdHf50xk%3D
- http://rb.symcb.com/rb.crl
- http://203.26.79.13/filestreamingservice//files/753bb2df-a166-494f-aa7d-5678b1ef0c56/pieceshash?cacheHostOrigin=dl.delivery.mp.microsoft.com
- http://203.26.79.13/filestreamingservice/files/753bb2df-a166-494f-aa7d-5678b1ef0c56?P1=1787851279&P2=404&P3=2&P4=AmtGTPaeA9%2f4PerXHgKIZk5fES1Hb69WDMaY3nDWD6kSRG7YSvsvBHKg86Vqs36KD5FJHY6W9UjLZuvs7OnZ2w%3d%3d&cacheHostOrigin=msedge.b.tlu.dl.delivery.mp.microsoft.com
- http://203.26.79.13/filestreamingservice//files/c74a5353-3e6a-42b7-94d6-9b96c560c89a/pieceshash?cacheHostOrigin=dl.delivery.mp.microsoft.com
- http://203.26.79.13/filestreamingservice/files/c74a5353-3e6a-42b7-94d6-9b96c560c89a?P1=1787851373&P2=404&P3=2&P4=czMOs0ttaorjPSwptInZAgObRZ%2fCnSsEEH2F1ZLVpQR2B5VtBCgP8%2f9K%2bF1wztj2o1pDBLE6SiFgFTZ5IyOyGw%3d%3d&cacheHostOrigin=msedge.b.tlu.dl.delivery.mp.microsoft.com
Embedded domains
- server.com
- tsymantec.com
- tsecurityresponse.symantec.com
- tsarc.com
- twww.sarc.com
- twww.sophos.com
- tsophos.com
- twww.mcafee.com
- tmcafee.com
- tliveupdate.symantecliveupdate.com
- twww.viruslist.com
- tviruslist.com
- tf-secure.com
- twww.f-secure.com
- tf-prot.com
- twww.f-prot.com
- tkaspersky.com
- tkaspersky-labs.com
- twww.avp.com
- tavp.com
- twww.kaspersky.com
- twww.networkassociates.com
- tnetworkassociates.com
- twww.ca.com
- tca.com
Embedded IP addresses
- 20.184.175.18
- 57.154.63.210
- 4.230.171.124
- 20.247.185.124
- 172.215.188.225
- 74.178.76.128
- 20.184.175.14
- 74.178.76.54
- 20.165.94.63
- 20.89.1.10
- 52.123.129.14
- 20.112.250.133
- 40.103.64.242
- 135.233.45.223
- 52.123.252.227
- 135.234.160.245
- 203.26.79.13
- 104.46.162.229
- 4.150.223.104
- 52.148.114.188
- 52.110.12.30
- 52.110.12.15
- 74.178.232.29
- 72.145.35.101
- 52.110.12.47
Registry keys
- HKCU\Software\Microsoft\Windows\CurrentVersion\Run
File paths
- C:\Program
- C:\WINDOWS\system32\drivers\etc\hosts
More Fsysna samples · Latest analyzed threats · ATT&CK coverage
Analyzed on MalwareAnalyzer by Cyble · Open interactive report