Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 ef5c8ecd7acddbce…

MALICIOUS

Office (OLE) / .XLS

142.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-03-24
MD5: 3bb92d58ee61eb3145c00eaa7a9c6c2c SHA-1: d2668988916d855d9b51c3226af76c3ea9617dc6 SHA-256: ef5c8ecd7acddbcee7469825744992090a6d232c1ccb5598d1beffa8816efab4
200 Risk Score

Malware Insights

Emotet · confidence 95%

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

The file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known technique for delivering malware. The macros construct strings that appear to be URLs, likely for downloading a second-stage payload. ClamAV detection further confirms its malicious nature, identifying it as Emotet. The reconstructed URLs are: Sy"&"s"&"W"&"o"&"w"&"64\d"&"ear"&"dar"&"cy.c"&"o"&"m/c"&"s"&"s/N"&"H"&"G"&"yT"&"TC"&"K/, d"&"ebr"&"oad"&"lin"&"k.c"&"om/br"&"och"&"u"&"re/D/, d"&"ijico"&"m.n"&"et/e"&"rr"&"or/5x"&"zX"&"dD/, f"&"t"&"p.co"&"m"&"pr"&"ib"&"e.co"&"m/w"&"p-a"&"dm"&"in/P"&"zg"&"r8q"&"e"&"xn/, and hr"&"an"&"e"&"ni"&"e.pe"&"re"&"ez"&"d-2"&"4.co"&"m/1/uEi"&"bu"&"Iqh"&"Zi4"&"oua/.

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-adc2d23d2dc26dd0-9950240-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-adc2d23d2dc26dd0-9950240-0
  • 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
eee0a3dec225fd0088c74c7ab34b064dd06b0d4f7198f4d9a113e7b902ce722a		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6706 bytes

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