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

Static analysis result for SHA-256 6d11d6a32bda7d7f…

MALICIOUS

Office (OLE) / .XLSX

147.0 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: aa9ee3db01b93eebe2fb381b79102fa7 SHA-1: 7a1b7318613dec267c987c903516cf175c78d128 SHA-256: 6d11d6a32bda7d7f0e9847c6d7fa6e020e819b36cb3bc4eaf11cf6a0cfe30697
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.005 Visual Basic T1203 Exploitation for Client Execution

The sample contains Excel 4.0 macros with an Auto_Open entry, indicating it is designed to execute automatically upon opening. Heuristics indicate the use of dangerous functions and environment evasion techniques. The document body claims the file is encrypted and prompts the user to enable editing and content, a common lure for macro-enabled malicious documents.

Heuristics 4

  • 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.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • XLM Auto_Open environment-evasion HALT gate high OLE_XLM_ENVIRONMENT_EVASION_HALT
    Excel 4.0 macro sheet auto-executes multiple GET.WORKSPACE / GET.WINDOW environment checks and halts execution when the host does not match the expected user environment. This is a common sandbox-evasion pattern in XLM malware and is stronger than a bare XLM macro-sheet indicator.
  • 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
c78e0437bb8f0ae8df085025addda3d46f09f8693f52ed60e4ba07f5ef73b008		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 172326 bytes

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