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

Static analysis result for SHA-256 499562d8c25e4126…

MALICIOUS

Office (OLE) / .XLS

53.5 KB Created: 2020-10-26 09:31:03 Authoring application: Microsoft Excel
MD5: f52cfba3c6ab2f8f8ac91b0fb3ce3386 SHA-1: a51eda210d79b443f51adc03a170bee5c640ceba SHA-256: 499562d8c25e412690894d1822016760c91140fbf77b3d17f2a487155449bf60
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Service Execution: Visual Basic T1566.001 Phishing: Spearphishing Attachment T1059.001 Command and Scripting Interpreter: PowerShell T1059.003 Command and Scripting Interpreter: Windows Command Shell

The file is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open macro that utilizes dangerous formula APIs, specifically 'RUN'. This suggests the macro is designed to execute external commands or payloads. The presence of environment evasion techniques further supports a malicious intent to compromise the system. The document body contains heavily obfuscated text, which is typical for lures in phishing or scam documents.

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.
  • XLM Auto_Open environment-evasion HALT gate high OLE_XLM_ENVIRONMENT_EVASION_HALT
    Excel 4.0 macro sheet auto-executes multiple GET.WORKSPACE / GET.WINDOW environment checks and halts execution when the host does not match the expected user environment. This is a common sandbox-evasion pattern in XLM malware and is stronger than a bare XLM macro-sheet indicator.
  • 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
40f39e1ddba01aa04b8e56715b4f6e3dd8bd199b3d49ace4628473e625945b7c		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 16451 bytes

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