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

Static analysis result for SHA-256 443ac29037109e08…

MALICIOUS

Office (OLE) / .XLS

71.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-06-07
MD5: 53193738ed4cc49cb2c17c93dd6e2e1e SHA-1: dac23ebc5af52681cb773224876c5adb9a60ea29 SHA-256: 443ac29037109e08cb760d259ac39cc3582a872128b50eddf02fe579f4295e64
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Service Execution: Visual Basic T1059.001 Command and Scripting Interpreter: PowerShell T1204.002 Malicious Link: Malicious File

The critical heuristic OLE_XLM_DANGEROUS_FN indicates the presence of dangerous Excel 4.0 macro functions, specifically the RUN function, within an Auto_Open macro. The DOC BODY section reveals that the macro concatenates strings to form URLs, such as 'https://sweetzone.co/js/XVK/'. This strongly suggests the macro's purpose is to download and execute a second-stage payload from these URLs. The use of Auto_Open and concatenated URLs points to 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
b4f0a647cf6176132ebc9ecde0dbe63bae14d0fc3c1b3805926fc56fef0b0f6a
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7650 bytes