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

Static analysis result for SHA-256 a4c4199d583d9eab…

MALICIOUS

Office (OLE) / .XLS

45.0 KB Created: 2020-10-30 08:59:00 Authoring application: Microsoft Excel
MD5: 4ccf72c802bbb1bf1380c17b43b70cdb SHA-1: 0fee8ef716733464be93a77dca31052f85da48e0 SHA-256: a4c4199d583d9eab80979ea558b4293ad59682b357866f4bf872b1d578179c07
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1059.001 PowerShell T1204.002 Malicious File

The critical heuristic OLE_XLM_AUTOOPEN_DEFINEDNAME indicates the presence of an Excel 4.0 Auto_Open macro. This macro is configured to execute dangerous functions, as flagged by OLE_XLM_DANGEROUS_FN, and includes environment evasion techniques. The macro sheet itself contains numerous string constants, but no explicit URLs or commands were recovered from the truncated script listing. The primary attack vector is the execution of arbitrary code via the Auto_Open macro.

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
9fcef32b5ceaaa1a35ee641b531b4a79d1e561b5c0eb8fff0fe35591f7e74fb3		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 13201 bytes

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