Malicious Office (OOXML) / .XLSX — malware analysis report

Static analysis result for SHA-256 b77e1ad08702a9c0…

MALICIOUS

Office (OOXML) / .XLSX

411.0 KB Created: 2020-05-04 14:35:56 UTC Authoring application: Microsoft Excel 16.0300
MD5: e3a14227e75be40d87b16ed05425b1b7 SHA-1: 4a85489448511f0db0ff5c4c9fc37489a0ec0a05 SHA-256: b77e1ad08702a9c016799930e4e8002dab1975d330cb09b42bb281eb56a05aa9
320 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1059.003 Windows Command Shell

The file is an Excel spreadsheet containing a Workbook_Open macro. This macro utilizes VBA character-shift decoding to execute a shell command. The ClamAV detection name 'Xls.Downloader.DridexGreen09213-9890103-0' strongly suggests a downloader functionality. The VBA script likely decodes a command to download and execute a secondary payload, which is a common technique for malware distribution.

Heuristics 8

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • VBA character-shift decoded Shell command critical OLE_VBA_ASC_CHR_SHIFT_SHELL
    VBA auto-exec macro stores an encoded command string, decodes it with a Mid/Asc/Chr character-shift loop, and passes the recovered text to Shell. This is a high-confidence command stager.
  • ClamAV: Xls.Downloader.DridexGreen09213-9890103-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.DridexGreen09213-9890103-0
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • Suspicious extracted artifact high EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • VBA project inside OOXML medium OOXML_VBA
    Document contains vbaProject.bin — VBA macros present
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.openxmlformats.org/spreadsheetml/2006/main
    • http://schemas.openxmlformats.org/officeDocument/2006/relationships
    • http://schemas.openxmlformats.org/markup-compatibility/2006
    • http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac
    • http://schemas.microsoft.com/office/spreadsheetml/2014/revision
    • http://schemas.microsoft.com/office/spreadsheetml/2015/revision2
    • http://schemas.microsoft.com/office/spreadsheetml/2016/revision3

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
4a22836f47b577a08f4fa81dc00228ef40c68ab0c988285dc98178eb8be56fe0		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 2001 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved macro source contains an auto-exec entry point and execution/download terms.
vbaProject_00.bin
592f559fab23188e251364c20cecca94eaa52ebc4a6d492677bc6bc5be824314		 vba-project OOXML VBA project: xl/vbaProject.bin 16384 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved macro source contains an auto-exec entry point and execution/download terms.

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