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MalwareBazaar Database

You are currently viewing the MalwareBazaar entry for SHA256 cf99121f4d88b15a0239eec425b3c196606c8d42ec5a27bb4fa4ff33883d2b66. While MalwareBazaar tries to identify whether the sample provided is malicious or not, there is no guarantee that a sample in MalwareBazaar is malicious.

Database Entry


GuLoader


Vendor detections: 9


Intelligence 9 IOCs YARA 1 File information Comments
Download sample Add tag Delete this sample Report a False Positive

SHA256 hash: cf99121f4d88b15a0239eec425b3c196606c8d42ec5a27bb4fa4ff33883d2b66
SHA3-384 hash: 3aa9c7babc47382a17a56de08c2cbd321c765a24b379d03bab8b09780504e1dc46a1f4a036c897091d2464302c0b57cb
SHA1 hash: ff08dfc67aef448993b4b4643e3375a5b4195742
MD5 hash: 5e2feecb6a80e75f00ea2d8c45c7121d
humanhash: lake-spaghetti-utah-three
File name:Justificante de pago.js
Download: download sample
Signature GuLoader
Create hunting rule
File size:47'222 bytes
First seen:2026-10-28 10:43:37 UTC
Last seen:Never
File type:Java Script (JS) js
MIME type:text/plain
ssdeep 768:c4w5qog6hiXFl8ArP9FDyGawnkJncau3ZG8po329KknD15jX7BtDgb0f:c4w5qmkWArP9ByGaw1ayZzygnDbcb0f
TLSH T156236BE0DC17147A4B6A7B6C6CA42639C5A98210C923C070F6DE970947C5ADCFBBD89F
Magika javascript
Reporter abuse_ch
Tags:ESP geo GuLoader js

Intelligence

File Origin
# of uploads :
1
# of downloads :
163
Origin country :
SE SE
Vendor Threat Intelligence
No detections
Verdict:
Clean
Score:
89.3%
Link:
https://cyber-fortress.com/docs/result/index.php?id=6ae1d2023a56bbccb37c0b81
Tags:
n/a
Verdict:
Suspicious
Threat level:
  5/10
Confidence:
100%
Tags:
obfuscated repaired
Link:
https://www.filescan.io/uploads/6ae1d1fd29d315ba35274712/reports/e4ce38b5-3437-46a9-9933-fc8c54d6e6ff/overview
Verdict:
Unknown
Link:
https://www.hybrid-analysis.com/sample/cf99121f4d88b15a0239eec425b3c196606c8d42ec5a27bb4fa4ff33883d2b66
Verdict:
Malicious
File Type:
js
First seen:
2026-10-28T06:54:00Z UTC
Last seen:
2026-10-30T08:36:00Z UTC
Hits:
~1000
Link:
https://opentip.kaspersky.com/cf99121f4d88b15a0239eec425b3c196606c8d42ec5a27bb4fa4ff33883d2b66/results?tab=lookup
Result
Threat name:
GuLoader
Create hunting rule
Detection:
malicious
Classification:
troj.expl.evad
Score:
100 / 100
Link:
https://www.joesandbox.com/analysis/1993919
Signature
Creates processes via WMI
Found suspicious powershell code related to unpacking or dynamic code loading
JavaScript source code contains functionality to generate code involving a shell, file or stream
Malicious sample detected (through community Yara rule)
Obfuscated command line found
Powershell connects to network
Sigma detected: WScript or CScript Dropper
Suspicious execution chain found
Switches to a custom stack to bypass stack traces
Windows Scripting host queries suspicious COM object (likely to drop second stage)
Writes to foreign memory regions
Wscript starts Powershell (via cmd or directly)
Yara detected GuLoader
Behaviour
Behavior Graph:
Download SVG
behaviorgraph top1 dnsIp2 2 Behavior Graph ID: 1993919 Sample: Justificante de pago.js Startdate: 28/10/2026 Architecture: WINDOWS Score: 100 27 drive.usercontent.google.com 2->27 29 drive.google.com 2->29 43 Malicious sample detected (through community Yara rule) 2->43 45 Yara detected GuLoader 2->45 47 JavaScript source code contains functionality to generate code involving a shell, file or stream 2->47 49 Sigma detected: WScript or CScript Dropper 2->49 9 wscript.exe 1 2->9         started        signatures3 process4 signatures5 51 Wscript starts Powershell (via cmd or directly) 9->51 53 Obfuscated command line found 9->53 55 Windows Scripting host queries suspicious COM object (likely to drop second stage) 9->55 57 2 other signatures 9->57 12 cmd.exe 1 9->12         started        process6 signatures7 59 Wscript starts Powershell (via cmd or directly) 12->59 15 powershell.exe 1 267 12->15         started        19 conhost.exe 12->19         started        21 cmd.exe 1 12->21         started        process8 dnsIp9 31 drive.usercontent.google.com 142.251.167.132, 443, 49744 GOOGLE-GoogleLLCUS United States 15->31 33 drive.google.com 172.253.62.113, 443, 49743 GOOGLE-GoogleLLCUS United States 15->33 35 Writes to foreign memory regions 15->35 37 Found suspicious powershell code related to unpacking or dynamic code loading 15->37 39 Switches to a custom stack to bypass stack traces 15->39 41 Powershell connects to network 15->41 23 backgroundTaskHost.exe 15->23         started        25 backgroundTaskHost.exe 15->25         started        signatures10 process11
Score:
99%
Verdict:
Malware
File Type:
SCRIPT
Link:
https://malprob.io/report/cf99121f4d88b15a0239eec425b3c196606c8d42ec5a27bb4fa4ff33883d2b66
Verdict:
inconclusive
YARA:
2 match(es)
Tags:
Javascript T1059.007
Link:
https://app.malva.re/file/5e2feecb6a80e75f00ea2d8c45c7121d
Detection:
n/a
Link:
https://mwdb.cert.pl/sample/cf99121f4d88b15a0239eec425b3c196606c8d42ec5a27bb4fa4ff33883d2b66/
Threat name:
Win32.Trojan.Generic
Create hunting rule
Status:
Suspicious
First seen:
2026-10-28 10:39:44 UTC
File Type:
Text
AV detection:
6 of 24 (25.00%)
Threat level:
  5/5
Detection(s):
Suspicious file
Link:
https://check.spamhaus.org/check/?searchterm=z6mreh2nrcyvuarz53cclm6bszqgzdkc5rncpo2put7thcb5fnta._file
Result
Malware family:
guloader
Create hunting rule
Score:
  10/10
Tags:
family:guloader defense_evasion discovery downloader execution privilege_escalation
Link:
https://tria.ge/reports/261028-msxjracs4r/
Behaviour
Suspicious behavior: EnumeratesProcesses
Suspicious behavior: MapViewOfSection
Suspicious use of AdjustPrivilegeToken
Suspicious use of WriteProcessMemory
Command and Scripting Interpreter: JavaScript
Executes a command shell one-liner
Reads the TCP/IP host and domain name from the registry
System Location Discovery: System Language Discovery
Drops file in Windows directory
Suspicious use of NtSetInformationThreadHideFromDebugger
Contacts third-party web service commonly abused for C2
Badlisted process makes network request
Family: Guloader,Cloudeye
Process spawned unexpected child process
Please note that we are no longer able to provide a coverage score for Virus Total.
Threat name:
Malicious File
Score:
1.00
Link:
https://yomi.yoroi.company/submissions/cf99121f4d88b15a0239eec425b3c196606c8d42ec5a27bb4fa4ff33883d2b66

YARA Signatures

MalwareBazaar uses YARA rules from several public and non-public repositories, such as YARAhub and Malpedia. Those are being matched against malware samples uploaded to MalwareBazaar as well as against any suspicious process dumps they may create. Please note that only results from TLP:CLEAR rules are being displayed.

Rule name:Sus_CMD_Powershell_Usage
Create hunting rule
Author:XiAnzheng
Description:May Contain(Obfuscated or no) Powershell or CMD Command that can be abused by threat actor(can create FP)

File information

The table below shows additional information about this malware sample such as delivery method and external references.

Comments