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

Static analysis result for SHA-256 20b764854102fc8d…

MALICIOUS

Office (OLE) / .XLS

31.0 KB Created: 2021-01-25 15:18:25 Authoring application: Microsoft Excel
MD5: f59a1803d8992fe736c67185f1d69bdf SHA-1: b21e00d69e1805ca5afd2e567e230b967c8489f2 SHA-256: 20b764854102fc8df5ef823666d5f472b91da90f50dca22e5d5e9484f3ed3ae9
160 Risk Score

Malware Insights

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

The sample is an Excel 4.0 (XLM) macro-enabled spreadsheet. It contains an Auto_Open macro, which is a common technique for executing malicious code upon opening the document. The document body explicitly instructs the user to 'Enable Editing' and 'Enable Content', indicating a lure to bypass security measures. The XLM macro sheet utilizes dangerous formula APIs, including the RUN function, suggesting it is designed to download and execute a second-stage payload. No specific IOCs were extracted from the macro itself.

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.
  • 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.
  • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
f7ea9f717f1427496bf5c090d1d9c462176b4735a18f56a4a9ca782fa9dab3f0
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 3324 bytes