UPX-Packed Upatre Trojan Acting as Downloader for Zbot and CryptoLocker


Zero‑Dwell Threat Intelligence Report

A narrative, executive‑ready view into the malware’s behavior, exposure, and reliable defenses.
Generated: 2025-11-05 07:16:19 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
fz9cnn4.exe
Type
PE32 executable (GUI) Intel 80386 (stripped to external PDB), for MS Windows, UPX compressed
SHA‑1
e89be0ad9c7f8f59bed6925df319c663278e8707
MD5
bef498240a1eaa9c20aaf03f72e47a90
First Seen
2025-10-06 08:38:43.709315
Last Analysis
2025-10-06 13:34:33.790965
Dwell Time
0 days, 7 hours, 33 minutes

Extended Dwell Time Impact

For 4+ hours, this malware remained undetected — a limited but sufficient window for the adversary to complete initial execution and establish basic system access.

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
2025-10-06 00:16:55 UTC First VirusTotal submission
2025-10-08 14:03:07 UTC Latest analysis snapshot 2 days, 13 hours, 46 minutes
2025-11-05 07:16:19 UTC Report generation time 30 days, 6 hours, 59 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: 73. Detected as malicious: 67. Missed: 6. Coverage: 91.8%.

Detected Vendors

  • Xcitium
  • +66 additional vendors (names not provided)

List includes Xcitium plus an additional 66 vendors per the provided summary.

Missed Vendors

  • CMC
  • Paloalto
  • TACHYON
  • TrendMicro
  • ViRobot
  • Yandex

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 (49.08% 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 187 49.08%
Registry 92 24.15%
File System 37 9.71%
Process 32 8.40%
Device 18 4.72%
Windows 9 2.36%
Com 6 1.57%

MITRE ATT&CK Mapping

  • T1027.002 – packed with UPX

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.aieov.com 13.248.169.48 United States Amazon Technologies Inc.
www.msftncsi.com 2.18.67.81 Europe Akamai Technologies

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
5isohu.com A
www.msftncsi.com A
www.aieov.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 4 udp
53 8 udp
3702 1 udp

UDP Packets

Source IP Dest IP Sport Dport Time Proto
192.168.56.13 192.168.56.255 137 137 7.1850221157073975 udp
192.168.56.13 224.0.0.252 55150 5355 7.066184043884277 udp
192.168.56.13 224.0.0.252 60010 5355 9.842180013656616 udp
192.168.56.13 224.0.0.252 62406 5355 7.278475999832153 udp
192.168.56.13 224.0.0.252 63527 5355 9.326303005218506 udp
192.168.56.13 239.255.255.250 52252 3702 7.652878999710083 udp
192.168.56.13 8.8.4.4 49311 53 11.171001195907593 udp
192.168.56.13 8.8.4.4 54879 53 26.621921062469482 udp
192.168.56.13 8.8.4.4 54881 53 11.965747117996216 udp
192.168.56.13 8.8.4.4 58697 53 40.99686813354492 udp
192.168.56.13 8.8.8.8 49311 53 12.16855502128601 udp
192.168.56.13 8.8.8.8 54879 53 25.62260603904724 udp
192.168.56.13 8.8.8.8 54881 53 12.965732097625732 udp
192.168.56.13 8.8.8.8 58697 53 39.9970760345459 udp

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

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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