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

Static analysis result for SHA-256 18030a9ea4cf60ea…

MALICIOUS

Office (OLE) / .XLS

71.0 KB Created: 2020-12-16 21:57:09 Authoring application: Microsoft Excel
MD5: 9ff9db49a165d7fae4bfeefbe4cf985d SHA-1: 5bb9ead40881ab04d740573bbb98b1dc2f9c2458 SHA-256: 18030a9ea4cf60ea858db8b302cdd94962069f232be6212787ad1ddca0bbbe54
200 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1203 Exploitation for Client Execution

The file contains Excel 4.0 macros, specifically an Auto_Open entry, which is a strong indicator of malicious intent. The macros are designed to execute a PowerShell command, evidenced by the 'SC_STR_POWERSHELL' and 'SE_LOLBIN_RUN_COMMAND' heuristics. This PowerShell command is obfuscated but appears to download and execute a second-stage payload from a URL starting with 'http://'.

Heuristics 5

  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • Suspicious cmd.exe invocation with execution flag high SC_STR_CMD
    Suspicious cmd.exe invocation with execution flag
  • Reference to PowerShell high SC_STR_POWERSHELL
    Reference to PowerShell
  • LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND
    Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
22df816dc33fd441bebb01320fc83f85b01d95af08a0bf385c52f77624c681e1		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1474 bytes

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