Malicious Office (OLE) / .XLSX — malware analysis report

Static analysis result for SHA-256 46897e102327e7b4…

MALICIOUS

Office (OLE) / .XLSX

4.76 MB Created: 2006-11-08 15:21:05 Authoring application: Microsoft Excel First seen: 2023-01-30
MD5: 8e06b45888197e6cc69d9edb18d35813 SHA-1: ec4d1060b8ec62e5b77473dc40584f17866feea1 SHA-256: 46897e102327e7b4f5cd3bab5a8a34328190232aa64201b32b1f11f58de09696
622 Risk Score

Malware Insights

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

The sample contains heavily obfuscated VBA macros, including Workbook_Open and Auto_Open routines, which are designed to execute code upon opening. Critical heuristics indicate the use of WScript.Shell and ShellExecute, along with an ActiveX event launching a decoded Excel4 macro, strongly suggesting a downloader or stager. The macros likely attempt to download and execute a second-stage payload from one of the embedded URLs, such as http://srcedit.pekori.jp/tool/share_e.txt.

Heuristics 15

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
  • VBA ActiveX event launches decoded Excel4 macro critical OLE_VBA_ACTIVEX_XLM_STAGER
    VBA code attached to an auto-firing ActiveX/UserForm control event (e.g. _Layout/_Change/_Painted) decodes a string with Replace/Split/Join/StrReverse/Chr and passes the recovered formula text to ExecuteExcel4Macro. This bridges VBA event activation into XLM formula execution to call Win32 APIs / drop payloads while evading AutoOpen and Shell keyword detection — a high-confidence macro stager, not a specific Office parser CVE.
  • 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.
  • x86 GetPC stub (CALL $+5; POP EBP) high SC_GETPC_CALL
    x86 GetPC stub (CALL $+5; POP EBP)
  • Reference to ShellExecute API high SC_STR_SHELLEXEC
    Reference to ShellExecute API
  • Reference to Windows Script Host high SC_STR_WSCRIPT
    Reference to Windows Script Host
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • Auto_Open macro high OLE_VBA_AUTO
    Auto_Open macro
  • Auto_Close macro high OLE_VBA_AUTOCLOSE
    Auto_Close macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
  • CallByName call high OLE_VBA_CALLBYNAME
    CallByName call
  • VBA macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code
  • 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://srcedit.pekori.jp/tool/share_e.txt
    • http://srcedit.pekori.jp/tool/share.txt
    • http://srcedit.pekori.jp/tool/method_e.txt
    • http://srcedit.pekori.jp/tool/method.txt
    • http://srcedit.pekori.jp/
    • http://news.yahoo.co.jp/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
f071c905f5c99e69ae09637fa79fee3d95154dec0cd7053fe8c54a61b24ada39		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 8388608 bytes

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