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

Static analysis result for SHA-256 57f0fc9a3aee0bc9…

MALICIOUS

Office (OOXML) / .XLSM

91.7 KB Created: 2015-06-05 18:17:20 UTC Authoring application: Microsoft Excel 16.0300
MD5: 5d5944b750d62b9db147481d40cb6261 SHA-1: a37ab95877bb0eca8258f9eb60d04d3593c1c428 SHA-256: 57f0fc9a3aee0bc95dd54a22ce66bdf850b3ba28498e57cfe5f28a95bae3faaf
60 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File

The sample is an XLSM file containing VBA macros. The embedded VBA code is heavily obfuscated but appears to reconstruct a URL and a filename. Specifically, it reconstructs the URL 'http://31.42.186.166/dkkh/vato.vbs' and the filename '\vuty.vbs'. The script also attempts to establish persistence by writing to the registry key 'HKCU\Software\Microsoft\Windows\CurrentVersion\Run\IAccessible2Proxy'. The GetObject heuristic firing further supports the malicious nature of the VBA code.

Heuristics 3

  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
  • 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
7c6a94c6a54d27228b7fbf9bfeb7b21fa43d0c459b970cfca9dc87b00ee8297c		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 1334 bytes
vbaProject_00.bin
2b263e86af2192fbb2b161bb347a0d1c2385b5015ff0d7669e0fa55e22c41ea9		 vba-project OOXML VBA project: xl/vbaProject.bin 15360 bytes

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