Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 0bb86fc69cf8bddb…

MALICIOUS

Office (OLE) / .XLS

78.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-05-15
MD5: 409889b06fef49e717bddfe8fbe19302 SHA-1: 65672e927210d8ad058cdec52b2f323aebb5f26d SHA-256: 0bb86fc69cf8bddb9cd6822978121b4331cdc1656054a6633bdd40a2e286afff
200 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file is an Excel 4.0 macro-enabled spreadsheet detected as Emotet by ClamAV. The XLM macros contain obfuscated strings that, when concatenated, form URLs pointing to potential second-stage payloads and a path for execution as C:\Windows\System32\t.exe. The presence of an Auto_Open macro and the use of dangerous formula APIs indicate an intent to automatically execute malicious code upon opening.

Heuristics 4

  • 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.
  • ClamAV: Xls.Downloader.Emotet-add2d22d2bc26dd0-9950243-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-add2d22d2bc26dd0-9950243-0
  • 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
214b0200160a0a56c6b45537e99f08bf5e131e2710192ec67ed6ddfaa9428b75
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6825 bytes