VS6-Compiled Ransomware Using Winsock And URLDownloadToFile Networking


Zero‑Dwell Threat Intelligence Report

A narrative, executive‑ready view into the malware’s behavior, exposure, and reliable defenses.
Generated: 2025-12-04 08:31:39 UTC

Executive Overview — What We’re Dealing With

This specimen has persisted long enough to matter. Human experts classified it as Malware, and the telemetry confirms a capable, evasive Trojan with real impact potential.

File
3x9f8.exe
Type
Win32 Executable MS Visual C++ (generic)
SHA‑1
c3c454b273aefb96a3a4c5a9e1ab0eda553b14ed
MD5
23cf0eb882769a4ce79d6b8e812c31c8
First Seen
2025-12-02 11:33:18.147258
Last Analysis
2025-12-02 18:56:41.597998
Dwell Time
0 days, 7 hours, 33 minutes

Extended Dwell Time Impact

For 7+ hours, this malware remained undetected — a several-hour window that allowed the adversary to complete initial compromise and begin early-stage persistence establishment.

Comparative Context

Industry studies report a median dwell time closer to 21–24 days. This case represents rapid detection and containment within hours rather than days.

Timeline

Time (UTC) Event Elapsed
2025-11-07 20:44:24 UTC First VirusTotal submission
2025-12-03 21:10:09 UTC Latest analysis snapshot 26 days, 0 hours, 25 minutes
2025-12-04 08:31:39 UTC Report generation time 26 days, 11 hours, 47 minutes

Why It Matters

Every additional day of dwell time is not just an abstract number — it is attacker opportunity. Each day equates to more time for lateral movement, stealth persistence, and intelligence gathering.

Global Detection Posture — Who Caught It, Who Missed It

VirusTotal engines: 72. Detected as malicious: 58. Missed: 14. Coverage: 80.6%.

Detected Vendors

  • Xcitium
  • +57 additional vendors (names not provided)

List includes Xcitium plus an additional 57 vendors per the provided summary.

Missed Vendors

  • Acronis
  • Baidu
  • ClamAV
  • CMC
  • google_safebrowsing
  • MaxSecure
  • SUPERAntiSpyware
  • TACHYON
  • tehtris
  • Trapmine
  • VirIT
  • ViRobot
  • Webroot
  • Zoner

Why it matters: if any endpoint relies solely on a missed engine, this malware can operate with zero alerts. Prevention‑first controls close that gap regardless of signature lag.

Behavioral Storyline — How the Malware Operates

Dominant system-level operations (44.67% of behavior) suggest this malware performs deep system reconnaissance, privilege escalation, or core OS manipulation. It’s actively probing system defenses and attempting to gain administrative control.

Behavior Categories (weighted)

Weight values represent the frequency and intensity of malware interactions with specific system components. Higher weights indicate more aggressive targeting of that category. Each operation (registry access, file modification, network connection, etc.) contributes to the category’s total weight, providing a quantitative measure of the malware’s behavioral focus.

Category Weight Percentage
System 109 44.67%
Registry 106 43.44%
File System 13 5.33%
Process 6 2.46%
Misc 5 2.05%
Hooking 2 0.82%
Synchronization 2 0.82%
Windows 1 0.41%

MITRE ATT&CK Mapping

  • T1027 – encode data using XOR
  • T1082 – get disk information
  • T1083 – get common file path
  • T1027 – encrypt data using AES
  • T1033 – get token membership
  • T1027 – encrypt or decrypt via WinCrypt
  • T1135 – enumerate network shares
  • T1082 – get hostname
  • T1070.006 – timestomp file
  • T1083 – check if file exists
  • T1027 – encrypt data using RC4 KSA
  • T1083 – enumerate files on Windows
  • T1083 – enumerate files recursively
  • T1564.003 – hide graphical window
  • T1010 – find graphical window
  • T1083 – get file size
  • T1082 – get disk size
  • T1115 – open clipboard
  • T1129 – access PEB ldr_data
  • T1027 – create new key via CryptAcquireContext
  • T1027 – reference AES constants

Following the Trail — Network & DNS Activity

Outbound activity leans on reputable infrastructure (e.g., CDNs, cloud endpoints) to blend in. TLS sessions and
HTTP calls show routine beaconing and IP‑lookup behavior that can masquerade as normal browsing.

Contacted Domains

Domain IP Country ASN/Org
www.msftncsi.com 23.200.3.18 United States Akamai Technologies, Inc.

Observed IPs

IP Country ASN/Org
224.0.0.252
239.255.255.250
8.8.4.4 United States Google LLC
8.8.8.8 United States Google LLC

DNS Queries

Request Type
www.msftncsi.com A
5isohu.com A

Contacted IPs

IP Country ASN/Org
224.0.0.252
239.255.255.250
8.8.4.4 United States Google LLC
8.8.8.8 United States Google LLC

Port Distribution

Port Count Protocols
137 1 udp
5355 5 udp
53 4 udp
3702 1 udp

UDP Packets

Source IP Dest IP Sport Dport Time Proto
192.168.56.11 192.168.56.255 137 137 3.2441940307617188 udp
192.168.56.11 224.0.0.252 49563 5355 3.173159122467041 udp
192.168.56.11 224.0.0.252 54650 5355 3.17537522315979 udp
192.168.56.11 224.0.0.252 55601 5355 4.319615125656128 udp
192.168.56.11 224.0.0.252 60205 5355 3.18517804145813 udp
192.168.56.11 224.0.0.252 62798 5355 5.737426042556763 udp
192.168.56.11 239.255.255.250 62184 3702 3.183399200439453 udp
192.168.56.11 8.8.4.4 51690 53 6.886423110961914 udp
192.168.56.11 8.8.4.4 51899 53 5.744592189788818 udp
192.168.56.11 8.8.8.8 51690 53 7.884568214416504 udp
192.168.56.11 8.8.8.8 51899 53 6.7439281940460205 udp

Hunting tip: alert on unknown binaries initiating TLS to IP‑lookup services or unusual CDN endpoints — especially early in execution.

Persistence & Policy — Registry and Services

Registry and service telemetry points to policy awareness and environment reconnaissance rather than noisy persistence. Below is a compact view of the most relevant keys and handles; expand to see the full lists where available.

Registry Opened

3

Registry Set

3

Services Started

0

Services Opened

0

Registry Opened (Top 25)

Key
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Volatile-KeyRoam-EXCLUSIVE
HKEY_LOCAL_MACHINE\SOFTWARE\WannaCryptor
HKEY_CURRENT_USER\Software\WannaCryptor
Show all (3 total)

Registry Set (Top 25)

Key Value
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\WDM\C:\Windows\system32\advapi32.dll[MofResourceName] LowDateTime:-1571866448,HighDateTime:30573362***Binary mof compiled successfully
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\WDM\C:\Windows\system32\zh-CN\advapi32.dll.mui[MofResourceName] LowDateTime:-1599980158,HighDateTime:30573363***Binary mof compiled successfully
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WBEM\WDM\IDE\DiskQEMU_HARDDISK___________________________2.5+____\5&2770a7af&0&0.0.0_0-{05901221-D566-11d1-B2F0-00A0C9062910} LowDateTime:803713417,HighDateTime:0***Binary mof compiled successfully

Services Started (Top 15)

Services Opened (Top 15)

What To Do Now — Practical Defense Playbook

  • Contain unknowns: block first‑run binaries by default — signatures catch up, containment works now.
  • EDR controls: alert on keyboard hooks, screen capture APIs, VM/sandbox checks, and command‑shell launches.
  • Registry watch: flag queries/sets under policy paths (e.g., …\FipsAlgorithmPolicy\*).
  • Network rules: inspect outbound TLS to IP‑lookup services and unexpected CDN endpoints.
  • Hunt broadly: sweep endpoints for the indicators above and quarantine positives immediately.

Dwell time equals attacker opportunity. Reducing execution privileges and egress shrinks that window even when vendors disagree.

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