Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 feb68eb6f44f1986…

MALICIOUS

Office (OOXML)

297.6 KB Created: 2019-10-01 12:18:50 UTC Authoring application: Microsoft Excel 14.0300
MD5: 936ab799e5b8a54f8354b589c6a28fa1 SHA-1: 9fd7f75575efec180f8579e59746691374265467 SHA-256: feb68eb6f44f1986d841a6c96c3f1ce1197cfe45a17660a8341224bb9d086f1e
458 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1218.011 Signed Binary Proxy Execution: Rundll32

The file contains a Workbook_Open macro that utilizes WScript.Shell and CreateObject to execute arbitrary commands, indicating a malicious intent to download and run a secondary payload. The presence of obfuscated VBA code and the use of LOLBins further support this assessment. The embedded URL http://www.eurekabpo.ru is a potential indicator of compromise.

Heuristics 13

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
  • LOLBin reference in VBA critical OLE_VBA_LOLBIN
    LOLBin reference in VBA
  • 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.
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • GetObject call high OLE_VBA_GETOBJ
    GetObject 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 project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Suspicious extracted artifact medium 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.
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)
  • Hidden worksheet (hidden, veryHidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 3 hidden sheet(s) — hidden sheets are commonly used to conceal macro code, staging data, or intermediate payload construction
  • 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 https://github.com/VBA-tools/VBA-JSON
    • http://www.vbaccelerator.com/home/VB/Code/Techniques/RunTime_Debug_Tracing/VB6_Tracer_Utility_zip_cStringBuilder_cls.asp
    • https://github.com/VBA-tools/VBA-JSON/pull/82
    • https://github.com/VBA-tools/VBA-UtcConverter
    • http://www.eurekabpo.ru
    • http://www.opensource.org/licenses/mit-license.php
    • http://code.google.com/p/vba-json/
    • http://msdn.microsoft.com/en-us/library/windows/desktop/ms724421.aspx
    • http://msdn.microsoft.com/en-us/library/windows/desktop/ms724949.aspx
    • http://msdn.microsoft.com/en-us/library/windows/desktop/ms725485.aspx
    • http://support.microsoft.com/kb/269370
    • http://www.ietf.org/rfc/rfc4627.txt
    • https://support.microsoft.com/en-us/kb/272138
    • http://www.w3.org/2001/XMLSchema-instance
    • http://www.opensource.org/licenses/mit-license.php)�

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
818aa435ef51ea453951ffc48c7d489b97159f5006f1c55216ff86ad4065a183		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 281414 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).
vbaProject_00.bin
5f900a5db2f87426f2c8337a0ba12c3d25f77956ec8c968649ea6e7a9f9beccb		 vba-project OOXML VBA project: xl/vbaProject.bin 495104 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 eval/decoder/string-building token(s).

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