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

Static analysis result for SHA-256 7d8ee0b754cd2a99…

MALICIOUS

Office (OLE) / .XLS

71.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-06-07
MD5: 7388ccc94da54ff692768a963266063c SHA-1: 4761f6bf7df6a3b13f31fdbfb6a8abbbafc80676 SHA-256: 7d8ee0b754cd2a993aedbb05a9ba3ab626b178f434b0e9225d08b53f6c3d2d08
140 Risk Score

Malware Insights

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

The critical heuristics OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN indicate the presence of an Excel 4.0 Auto_Open macro. This macro is configured to execute a list of URLs, which are likely used to download and execute a second-stage payload. The macro uses the RUN function, a known dangerous API in XLM macros, to initiate this process. The extracted URLs are the primary indicators of compromise.

Heuristics 3

  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
5111faade6798439ce43161a25c95a0c795073df8f05008e90c40cef2fd124d6
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7798 bytes