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

Static analysis result for SHA-256 b81d1407ef833190…

MALICIOUS

Office (OLE) / .XLS

31.0 KB Created: 2021-02-05 13:42:58 Authoring application: Microsoft Excel
MD5: 8ec0149bb9459e744bf7dde17d90e179 SHA-1: 79112b09e45c556b2f55aa33a377438bd5e1b832 SHA-256: b81d1407ef833190714ccb794e46bfccf1c0ad77ae36f32bda09e34f23f0a4fc
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.002 User Execution: Malicious File T1059.005 PowerShell

The sample is an Excel 4.0 macro-enabled spreadsheet. It contains an Auto_Open macro, which is a known technique for executing malicious code upon opening the document. The document body explicitly instructs the user to 'Enable Editing' and 'Enable Content', indicating a social engineering lure to bypass security measures. The presence of the Auto_Open function and the lure strongly suggest this file is designed to execute arbitrary code.

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
ca298c25676fecc121c16b9309384ea8f0490192c63b879cbe48fe4b20e6b28c		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 3293 bytes

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