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

Static analysis result for SHA-256 8ca6ffa893cc2512…

MALICIOUS

Office (OLE) / .XLS

248.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-02-24
MD5: 9bce9020dd71cb4ed4d4540aaa017c16 SHA-1: 1cc77fae548cc761886cb7d162491940dde5dc70 SHA-256: 8ca6ffa893cc2512f843d08c90fff8bcfd58dff6201b76c4583dfa53dd151ae6
302 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1218.011 System Binary Proxy Execution: Rundll32 T1059.001 PowerShell

The file contains Excel 4.0 macros, specifically an Auto_Open macro, which is a critical finding. The macro utilizes dangerous functions and reconstructs a command line involving 'regsvr32.exe' to download and execute a payload from one of the five embedded URLs. The ClamAV detection 'Doc.Downloader.EmotetRed02220-9940038-0' further supports its malicious nature as a downloader. The macro's intent is to download and execute a second-stage payload from the provided URLs.

Heuristics 7

  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • URL reconstructed from XLM cell array (5 URLs) critical OLE_XLM_CELL_ARRAY_URL
    Excel 4.0 macro sheet stages its payload URL across the BIFF8 Shared String Table (one quoted-char SST entry concatenated with & at runtime) or across individual numeric cells (one ASCII charcode per cell). The reconstructed URL is invisible to literal-bytes URL extraction because it is never contiguous in the workbook stream. URLs were recovered by walking the BIFF8 record stream and decoding SST entries plus LABELSST/RK/NUMBER cells.
  • ClamAV: Doc.Downloader.EmotetRed02220-9940038-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.EmotetRed02220-9940038-0
  • LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND
    Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.
  • 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://dalgahavuzu.com/pwkfky/LF0WU/
    • https://dolphinsupremehavuzrobotu.com/yrrct/QcbxhqCQ/
    • https://sandiegoinsuranceagents.com/cgi-bin/XK1VSXZddLdN/
    • https://kinetekturk.com/e2ea69p/9U52O7jTobF8J/
    • https://isguvenligiburada.com/xcg/uZSU/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
7f379bcff2385f1253d72017586eefb5fb5a96855b7e7be1bfb5ca7795a0eb45		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6628 bytes

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