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

Static analysis result for SHA-256 9fcc4c5656f566ed…

MALICIOUS

Office (OLE) / .XLSX

177.0 KB Created: 2012-11-08 09:24:33 Authoring application: Microsoft Excel
MD5: b3cbdb5234e55bb09d0aba46381b1e7c SHA-1: d4a342f73f9d726e65098a7f21128b1176d12d21 SHA-256: 9fcc4c5656f566ed05910373e42b8f1b306ee63cc35943cb74eb0c07dbc14b06
628 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1059.003 Windows Command Shell T1218.011 System Binary Proxy Execution: Rundll32 T1059.005 Visual Basic T1059.006 Python

The sample is an Excel file containing VBA macros, specifically triggering on Workbook_Open and Auto_Open events. It utilizes WScript.Shell and WMI (Win32_Process.Create) to execute arbitrary commands, a common technique for downloading and running second-stage payloads. The presence of the ClamAV signature 'Xls.Virus.Mailcab-6702020-0' further confirms its malicious nature. The document body content appears to be a legitimate-looking engineering document, serving as a lure to trick users into enabling macros.

Heuristics 16

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
  • VBA WMI Win32_Process launcher critical OLE_VBA_WMI_PROCESS_CREATE
    VBA macro builds or references a WMI moniker for Win32_Process and invokes .Create to start a command. This is a high-confidence macro execution chain that often hides the WMI class name through string concatenation or helper functions.
  • ClamAV: Xls.Virus.Mailcab-6702020-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Virus.Mailcab-6702020-0
  • Reference to Windows Script Host high SC_STR_WSCRIPT
    Reference to Windows Script Host
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • Auto_Open macro high OLE_VBA_AUTO
    Auto_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.
  • Clipboard command execution lure high SE_CLIPBOARD_COMMAND_LURE
    Document tells the user to copy or paste clipboard content into Run, PowerShell, cmd, or another shell-like execution context
  • Suspicious extracted artifact high 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.
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.
  • VBA macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • 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
b9c2dbe27fdff918bf63d672ebea8d816aa9b3f90e4e4faa6f8a79b534a6154e		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 27717 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 7 shell/COM execution token(s). Carved artifact contains 9 Chr/ChrW string-construction calls. Carved macro source contains an auto-exec entry point and execution/download terms.

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