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

Static analysis result for SHA-256 9ad140abaff79c13…

MALICIOUS

Office (OLE) / .XLS

71.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-06-07
MD5: ab4794a0d0589701937efcec95043987 SHA-1: 4316f698d9cce158109c7c7c2969e1a118a63945 SHA-256: 9ad140abaff79c135ed4d4ea46cbb104d7b6b0678fe743ac9ab0fde12995a9c1
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open function, which is a critical indicator of malicious intent. The macros are designed to execute dangerous functions, including the RUN API, suggesting it attempts to download and execute a second-stage payload. The embedded URLs are highly suspicious and likely serve as the source for this payload. The presence of the Auto_Open function and the use of dangerous APIs strongly indicate a downloader or initial access mechanism.

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