MalwareBazaar Database

You are currently viewing the MalwareBazaar entry for SHA256 b7d4f66a98e928dfb18d41021e5ad11043a3fc473c794edf481e8aa8c7cc9255. 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

SilentBuilder

Vendor detections: 11

Maldoc score: 5

Intelligence 11 IOCs YARA 10 File information Comments

SHA256 hash:	b7d4f66a98e928dfb18d41021e5ad11043a3fc473c794edf481e8aa8c7cc9255
SHA3-384 hash:	5890a996fb22af4aa2865e2f98cb90f41dc7268addac1aa7c28cc0cd7c82e576b1531edcf3e49c5e682ec2fd1b05df59
SHA1 hash:	67ac98ed09742ddb0a1ab68fc590c73cb2f79b1b
MD5 hash:	87fc72adcb395eb083e076dc1cfa20c7
humanhash:	lima-wyoming-mobile-red
File name:	case#_887219283_928831210.xls
Download:	download sample
Signature	SilentBuilder Create hunting rule
File size:	127'488 bytes
First seen:	2021-03-12 18:19:00 UTC
Last seen:	2021-03-12 19:35:20 UTC
File type:	xls
MIME type:	application/vnd.ms-excel
ssdeep	3072:8Kpb8rGYrMPe3q7Q0XV5xtezEsi8ZM+3UBjyqgF2ikieW2DXewVZawQ:8Kpb8rGYrMPe3q7Q0XV5xtuEsi8ZM++U
TLSH	2DC39D46F6F6AC98D71183341BE742ADA321EC230E6A17873258B311BFB95E00F17796
Reporter	p5yb34m
Tags:	CobaltStrike SilentBuilder TA505 xls

p5yb34m

.dll:
http://digitaldays.ro/site/brandupi.php

Office OLE Information

This malware samples appears to be an Office document. The following table provides more information about this document using oletools and oledump.

OLE id

Maldoc score: 5

Application name is Microsoft Excel

Office document is in OLE format

OLE dump

MalwareBazaar was able to identify 3 sections in this file using oledump:

Section ID	Section size	Section name
1	4096 bytes	DocumentSummaryInformation
2	4096 bytes	SummaryInformation
3	116747 bytes	Workbook

OLE vba

MalwareBazaar was able to extract and deobfuscate VBA script(s) the following information from OLE objects embedded in this file using olevba:

Type	Keyword	Description
AutoExec	Auto_Open	Runs when the Excel Workbook is opened
Suspicious	EXEC	May run an executable file or a system
Suspicious	Hex Strings	Hex-encoded strings were detected, may be used to obfuscate strings (option --decode to see all)

Intelligence

File Origin

# of uploads :

# of downloads :

1'673

Origin country :

n/a

Vendor Threat Intelligence

Malware family:

n/a

ID:

File name:

case_3.xls

Verdict:

Malicious activity

Analysis date:

2021-03-12 18:09:56 UTC

Tags:

macros ta505

Link:

https://app.any.run/tasks/2c5cf36b-7fd1-4034-9dfb-2834fc16e6af

Note:

ANY.RUN is an interactive sandbox that analyzes all user actions rather than an uploaded sample

Verdict:

Malicious

File type:

application/vnd.ms-excel

Has a screenshot:

False

Contains macros:

True

Detection:

n/a

Link:

https://www.capesandbox.com/analysis/123982/

Detection(s):

TwinWave.EvilDoc.Excel4DragoTrainingMontage.20210204.UNOFFICIAL

TwinWave.EvilDoc.QakySoWacky.M2.20210218.UNOFFICIAL

Result

Verdict:

Malware

Maliciousness:

Behaviour

Creating a window

DNS request

Creating a file

Creating a process with a hidden window

Sending an HTTP GET request

Launching a process by exploiting the app vulnerability

Result

Verdict:

Malicious

File Type:

Legacy Office File

Link:

https://app.docguard.net/b7d4f66a98e928dfb18d41021e5ad11043a3fc473c794edf481e8aa8c7cc9255/results/dashboard

Payload URLs

URL

File name

_xlfn.TEXTJOIN

WorkBook

Document image

Image:

Download PNG

Result

Verdict:

MALICIOUS

Details

Autostarting Excel Macro Sheet

Excel contains Macrosheet logic that will trigger automatically upon document open.

Result

Threat name:

Hidden Macro 4.0 CobaltStrike

Detection:

malicious

Classification:

troj.expl.evad

Score:

100 / 100

Link:

https://www.joesandbox.com/analysis/638149

Signature

Document exploit detected (drops PE files)

Document exploit detected (process start blacklist hit)

Document exploit detected (UrlDownloadToFile)

Drops PE files to the user root directory

Found Excel 4.0 Macro with suspicious formulas

Malicious sample detected (through community Yara rule)

Multi AV Scanner detection for domain / URL

Office document tries to convince victim to disable security protection (e.g. to enable ActiveX or Macros)

Office process drops PE file

Sigma detected: Microsoft Office Product Spawning Windows Shell

System process connects to network (likely due to code injection or exploit)

Yara detected CobaltStrike

Behaviour

Behavior Graph:

Download SVG

Detection:

n/a

Link:

https://mwdb.cert.pl/sample/b7d4f66a98e928dfb18d41021e5ad11043a3fc473c794edf481e8aa8c7cc9255/

Threat name:

Script.Trojan.Wacatac

Status:

Malicious

First seen:

2021-03-12 18:19:04 UTC

AV detection:

2 of 47 (4.26%)

Threat level:

5/5

Detection(s):

Suspicious file

Link:

https://check.spamhaus.org/check/?searchterm=w7kpm2uy5eun7mmniebb4wwrcbb2h7chhr4u5x2id2fkrr6msjkq._file

Result

Malware family:

cobaltstrike

Score:

10/10

Tags:

family:cobaltstrike backdoor macro trojan xlm

Link:

https://tria.ge/reports/210312-zf8kkndh1n/

Behaviour

Checks processor information in registry

Enumerates system info in registry

Modifies Internet Explorer settings

Suspicious behavior: AddClipboardFormatListener

Suspicious use of FindShellTrayWindow

Suspicious use of SetWindowsHookEx

Suspicious use of WriteProcessMemory

Loads dropped DLL

Blocklisted process makes network request

Cobaltstrike

Process spawned unexpected child process

Malware Config

C2 Extraction:

http://onealabamasport.com:443/jquery-3.3.1.min.js
http://onealabamasport.com:443/jquery-3.3.2.slim.min.js

Dropper Extraction:

http://digitaldays.ro/site/brandupi.php

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/b7d4f66a98e928dfb18d41021e5ad11043a3fc473c794edf481e8aa8c7cc9255

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:	Email_stealer_bin_mem Create hunting rule
Author:	James_inthe_box
Description:	Email in files like avemaria

Rule name:	Excel_Hidden_Macro_Sheet Create hunting rule

Rule name:	INDICATOR_DOC_PhishingPatterns Create hunting rule
Author:	ditekSHen
Description:	Detects OLE, RTF, PDF and OOXML (decompressed) documents with common phishing strings

Rule name:	IPPort_combo_mem Create hunting rule
Author:	James_inthe_box
Description:	IP and port combo

Rule name:	Select_from_enumeration Create hunting rule
Author:	James_inthe_box
Description:	IP and port combo

Rule name:	SharedStrings Create hunting rule
Author:	Katie Kleemola
Description:	Internal names found in LURK0/CCTV0 samples

Rule name:	SUSP_EnableContent_String_Gen Create hunting rule
Author:	Florian Roth
Description:	Detects suspicious string that asks to enable active content in Office Doc
Reference:	Internal Research

Rule name:	SUSP_Excel4Macro_AutoOpen Create hunting rule
Author:	John Lambert @JohnLaTwC
Description:	Detects Excel4 macro use with auto open / close

Rule name:	UAC_bypass_bin_mem Create hunting rule
Author:	James_inthe_box
Description:	UAC bypass in files like avemaria

File information

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

Malspam

SilentBuilder

xls b7d4f66a98e928dfb18d41021e5ad11043a3fc473c794edf481e8aa8c7cc9255

(this sample)

Delivery method

Distributed via e-mail attachment

Cape

https://www.capesandbox.com/analysis/123982/

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