Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 4a8c152ef7c7e3ce…

MALICIOUS

Office (OLE)

371.5 KB Created: 2018-07-26 00:26:51 Authoring application: Microsoft Excel
MD5: 15d1252024d046b76737f80017b31b5e SHA-1: 9d61edbf4819eb9ee8e6de03120ee06e1a8b592e SHA-256: 4a8c152ef7c7e3ced93e8629691f6f66bb67f78c4e17caf0198db18300b19acf
288 Risk Score

Malware Insights

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

The file contains a Workbook_Open VBA macro that is heavily obfuscated and uses CreateObject to execute a command. The script constructs a command by concatenating strings and environment variables, ultimately leading to the execution of a script file named '//klDialogDeleteFormat.sct' via mshta.exe. This indicates the macro is designed to download and execute a second-stage payload.

Heuristics 8

  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
  • Reference to Windows Script Host high SC_STR_WSCRIPT
    Reference to Windows Script Host
  • Reference to mshta.exe high SC_STR_MSHTA
    Reference to mshta.exe
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • VBA macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
78fbdf6960a16588e3c52890d7916c78aca8ab670a40a5e04f2f6a0b0623e55d		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 1143 bytes

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