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

Static analysis result for SHA-256 810a66989b16d6b8…

MALICIOUS

Office (OLE) / .XLS

85.0 KB Created: 2020-07-02 15:46:44 Authoring application: Microsoft Excel
MD5: 58b62b641066a1ea49e34a2f711a1854 SHA-1: 4bf1830ed130fe97e50807b1a4ba4749c8fefe75 SHA-256: 810a66989b16d6b8005d23e80750031849cdfdd5beded1534b7f2d44cd4352f5
160 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

This XLS file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical indicator of malicious intent. The presence of dangerous formula APIs like RUN suggests the macro is designed to execute arbitrary commands. The heuristic 'Macro/content-enable lure' further indicates that the document likely attempts to trick the user into enabling macros. The macro's primary function appears to be executing a command, likely to download and run a second-stage payload, which is a common delivery mechanism for malware.

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
80dc9bb29c9a64b3fdb9ba81ca4b976404b99500f7b93b11000e689fe63d7420
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 31042 bytes