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

Static analysis result for SHA-256 7848297de8cb3a65…

MALICIOUS

Office (OLE) / .XLS

38.0 KB Created: 2022-12-01 20:13:32 Authoring application: Microsoft Excel First seen: 2022-12-02
MD5: f79fc28e4f8f45673f7cd89ebfdfd8f2 SHA-1: c42880c461fd52ac284659592b00979bfb2b4e26 SHA-256: 7848297de8cb3a65afb8413171818248db22bc4f47f57aa0f4aa5effda1ca94e
368 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1105 Ingress Tool Transfer T1059.003 Windows Command Shell

The Workbook_Open macro is obfuscated and uses CreateObject to download a file from "http://transfer.sh/get/nk0tQV/excel.exe" and save it as "office.exe" in the user's temporary directory. It then attempts to execute the downloaded file, indicating a downloader or droppper functionality.

Heuristics 9

  • VBA downloads and writes a file to disk critical OLE_VBA_HTTP_DROP_EXEC
    VBA reads an HTTP response body and writes it to disk (ADODB.Stream SaveToFile). Combined with the auto-exec/Shell paths this is a download-drop dropper even when the COM ProgIDs are built dynamically to evade keyword scanning.
  • 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.
  • ClamAV: Xls.Malware.Sload-7135989-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Malware.Sload-7135989-0
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
  • 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.
  • VBA macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
f039fa30a92520d488551e0b0f6f0704dff1c52daeb646c57ef68bfd062a78a2		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 4453 bytes

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