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

Static analysis result for SHA-256 5b424584f92912bc…

MALICIOUS

Office (OLE) / .XLS

145.5 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: 83ac39d1741a697ad63598818fefb58b SHA-1: 364a1f71eaafefe89860d7a9c6773297a0d50e5f SHA-256: 5b424584f92912bcce18e13782e8f25e042a258e6af080a7e26d578ddd713e7b
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The sample is an Excel file containing Excel 4.0 macros, specifically an Auto_Open macro designed to execute automatically. The document body claims the file is encrypted and prompts the user to enable editing and content, a common social engineering tactic to bypass security measures and execute malicious code. The presence of the Auto_Open macro and the environment evasion techniques indicate a high likelihood of malicious intent, likely to download and execute a second-stage payload.

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
526a208e5830ea3e2e2fb54f4a879dfc649714a0fdf93e78c5a638020362bc05		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 174057 bytes

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