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

Static analysis result for SHA-256 167a95957c768962…

MALICIOUS

Office (OLE) / .XLSX

136.0 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: a4a76c9ae8211bcd264532909f8c2875 SHA-1: 4b9dcfd9c92c956f17a48a1b9dd2299f328a08e5 SHA-256: 167a95957c76896288917c0d90f05bfa1c5761c048199fafd334d414b0296f45
222 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1105 Ingress Tool Transfer

The file contains VBA macros, including Auto_Open and Auto_Close, which are commonly used to execute malicious code upon opening or closing a document. Critical heuristics indicate obfuscated API calls to 'URLDownloadToFile', suggesting the macro's intent is to download a second-stage payload from one of the embedded URLs. The ClamAV detection further confirms its malicious nature as a downloader.

Heuristics 6

  • Dangerous API name reassembled from split string literals critical OLE_VBA_SPLIT_KEYWORD_OBFUSCATION
    VBA concatenates short string literals that reassemble a dangerous API/ProgID/LOLBin name (e.g. Scripting.FileSystemObject, WScript.Shell, powershell, URLDownloadToFile) which appears in no single literal. Splitting an API name across string concatenation is done only to evade keyword scanning.
  • ClamAV: Doc.Downloader.Docusign112100-9908075-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Docusign112100-9908075-0
  • Auto_Open macro high OLE_VBA_AUTO
    Auto_Open macro
  • Auto_Close macro high OLE_VBA_AUTOCLOSE
    Auto_Close macro
  • VBA macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code
  • 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://188.165.62.61/
    • http://79.141.171.170/
    • http://185.244.150.138/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
954b17b40618c472edefb57d86095b1fb0c0b22bc019811f22885378cc130af1
vba-macro oletools.olevba.extract_macros (decoded VBA source) 5040 bytes