Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 cd99b899c5a3d6dd…

MALICIOUS

Office (OLE) / .XLS

216.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-11-02
MD5: d3b182de8c99553a9f2b6d0f3f030a4f SHA-1: d5bd989ffde2f67133b6404f9f234d13e618c206 SHA-256: cd99b899c5a3d6ddb22969605b079375da897362b4d599fc9eebb1e21115a31d
200 Risk Score

Malware Insights

Emotet · confidence 95%

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

The file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known technique for executing malicious code. ClamAV detection identifies it as Xls.Downloader.Emotet, indicating its role as a downloader. The use of dangerous formula APIs like RUN further supports the malicious intent.

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-b649c93692b4c9d9-9976616-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-b649c93692b4c9d9-9976616-0
  • 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
9769df32b31dca739db0ef5d2698aee07ce71addcfc3c157c359d4c3e51dbff9
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8159 bytes