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

Static analysis result for SHA-256 ef814bb7c9efb8d0…

MALICIOUS

Office (OLE) / .DOC

256.0 KB Created: 2020-04-28 11:51:53 Authoring application: Microsoft Excel
MD5: d1e2f6d5f205481c65122cb1a1fc4825 SHA-1: 6e2f691e7c6992148e4ae56aec9933c2bed285e7 SHA-256: ef814bb7c9efb8d0f603df75f3dac33648aedfe6732f74f3a97ad1201e87979c
240 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1059.001 PowerShell T1059.003 Windows Command Shell

This Excel 4.0 macro-enabled document contains an Auto_Open macro, indicated by the OLE_XLM_AUTOOPEN and OLE_XLM_AUTOOPEN_DEFINEDNAME heuristics. The macro utilizes dangerous functions, including ShellExecute and URLDownloadToFile, as flagged by SC_STR_SHELLEXEC and SC_STR_URLDOWNLOAD. This suggests the macro is designed to download and execute a secondary payload from a remote location. The document body contains obfuscated text, which is typical for macro-based lures.

Heuristics 5

  • Reference to URLDownloadToFile API critical SC_STR_URLDOWNLOAD
    Reference to URLDownloadToFile API
  • 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.
  • Reference to ShellExecute API high SC_STR_SHELLEXEC
    Reference to ShellExecute API
  • 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
484fd313fdb8640fc25492c455bbab61ae4ca3544e15eed67c557749a98dd34a
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 47300 bytes