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

Static analysis result for SHA-256 4fa6c2c7fb5cc575…

MALICIOUS

Office (OLE) / .XLS

42.0 KB Created: 2020-09-28 00:53:43 Authoring application: Microsoft Excel
MD5: 1c4079fe194f835b0f30fbfdf69fdc0a SHA-1: 628e7d8aea95ea6cda69f914085f1807bdf90d8e SHA-256: 4fa6c2c7fb5cc57569089d245f0dd1cbd72984a31b3f58c253507138320a3235
180 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open macro that utilizes dangerous functions, including a 'RUN' command and environment evasion techniques. This suggests the macro is designed to execute arbitrary commands upon opening, likely to download and run a second-stage payload. No specific IOCs were extracted, but the presence of the Auto_Open function and the use of dangerous APIs are strong indicators of malicious intent.

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
3f3b4782020a4feb6132fada8e9b2744fa38889fa3f553a5de108251d3dd2be0		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 8172 bytes

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