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

Static analysis result for SHA-256 744cfa43336e1628…

MALICIOUS

Office (OLE) / .XLS

68.0 KB Created: 2019-10-22 07:10:34 Authoring application: Microsoft Excel
MD5: 25d108bb3181b08a9fb2edc6713323b2 SHA-1: e9983f38587f57213137c534be223a8931e33e2c SHA-256: 744cfa43336e162820a03f1a6b2ff7fa9d2471f92f14691c5f59156c634d8015
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file contains Excel 4.0 macros, specifically an Auto_Open entry, which is a known technique for executing malicious code upon opening the workbook. The macro uses a concatenated string to construct a URL, 'http://paste.ee/r/r87uc', and then uses Net.WebClient to download and execute a second-stage payload from this URL. This indicates a downloader or droppper functionality.

Heuristics 4

  • 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.
  • Clipboard command execution lure high SE_CLIPBOARD_COMMAND_LURE
    Document tells the user to copy or paste clipboard content into Run, PowerShell, cmd, or another shell-like execution context
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
7dddc38a50bb2e03e21b4f250ed6aa29ab0e3f35feeb1b22f530d7e1d8ca3e5b		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1937 bytes

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