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

Static analysis result for SHA-256 753717e5a824ebd3…

MALICIOUS

Office (OLE) / .XLS

71.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-06-08
MD5: 84e1924e689c5d40f5255dbaa8b281db SHA-1: df34258b1a64938f6e8247832b7080673ddc9184 SHA-256: 753717e5a824ebd3ce08aeafc07dededaec0266eeb72a186782c8596c41f2db2
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Service Execution: Service Execution T1204.002 Malicious File: User Execution: Malicious File

The critical heuristics OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN indicate the presence of an Excel 4.0 Auto_Open macro that uses dangerous functions like RUN. The extracted URLs are likely used to download and execute a second-stage payload. The macro's intent is to automatically run upon opening the spreadsheet, facilitating the download and execution of malicious content.

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