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

Static analysis result for SHA-256 24c01e2ef72c8091…

MALICIOUS

Office (OLE) / .XLS

65.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-05-24
MD5: f6b8cbbd00d17d6a1a4ae980ec4fa820 SHA-1: 945aceccbc433b2b577f393043157252b40f57a7 SHA-256: 24c01e2ef72c8091f60272a8adaa25bf1be3bc4c2bea84b48e14b685375d640e
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open macro, which is a critical indicator of malicious intent. The macros are designed to construct URLs by concatenating strings, such as 'http://ocalogulari.com/inc/Wcm82enrs8/', which are then likely used to download and execute a secondary payload. The presence of the Auto_Open function and the construction of URLs strongly suggest a downloader or droppper functionality.

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
67f6b164c4d6ea1ea8efe2ccdff056dde7fd1072da2bb20afe3b275864086c71
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7678 bytes