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

Static analysis result for SHA-256 77d8254aa50496a8…

MALICIOUS

Office (OLE) / .XLS

197.5 KB Created: 2020-07-01 23:17:53 Authoring application: Microsoft Excel
MD5: 0dd976de7791a9839f9bc1ef3b9ad2e9 SHA-1: 9489320f62ebf2984b3add653edd7d2916161402 SHA-256: 77d8254aa50496a831b9e63992ba472f11458e36abdce22b07c5c6eeeb1815d4
220 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known technique for executing malicious code. Heuristics indicate the presence of dangerous formula APIs and environment evasion, suggesting an attempt to download and execute a payload. The 'Macro/content-enable lure' heuristic further supports that the document is designed to trick users into enabling macros, which is a common initial access vector for malicious documents.

Heuristics 5

  • 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 close gate critical OLE_XLM_ENVIRONMENT_EVASION_CLOSE
    Excel 4.0 macro sheet auto-executes environment checks with GET.WORKSPACE / GET.WINDOW, then shows a fake corruption/error message and closes the workbook when the host fails those checks. This is a malware sandbox-evasion pattern, even when the later payload stage is hidden behind obfuscated defined-name flow.
  • 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.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
4ebc5ef4abbf91bffb9af40a8cec17485366f359ded398cbec69f5cfc32dea70		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 78379 bytes

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