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

Static analysis result for SHA-256 17bd3e705cb89011…

MALICIOUS

Office (OLE) / .XLS

149.5 KB Created: 2021-07-24 09:17:42 Authoring application: Microsoft Excel
MD5: 4b63d995e59be2ef2b778ac7d93a9df2 SHA-1: 6be5991a8468a947c8020a668fba4f7b9312ef48 SHA-256: 17bd3e705cb89011155e7e1cba7967d7fb6c4c5f58f020726e8f12934bfa08d3
490 Risk Score

Malware Insights

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

This XLS file contains heavily obfuscated VBA macros, including a Workbook_Open auto-execution routine. The macros utilize WScript.Shell and CreateObject to download and execute a second-stage payload, as indicated by the 'OLE_VBA_HTTP_DROP_EXEC' heuristic. The specific download URL is obfuscated but the intent is clear: to fetch and run additional malicious content.

Heuristics 12

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
  • 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.Macro.Obfuscation-9804250-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Macro.Obfuscation-9804250-0
  • Reference to Windows Script Host high SC_STR_WSCRIPT
    Reference to Windows Script Host
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject 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)
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
2b0dbc45c3f0320338e698b621d63d9515c0c1c6cf4cbe25eec7d74141c59d13		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 53690 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 112 long base64-like blob(s).

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