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

Static analysis result for SHA-256 49638c7502de579d…

MALICIOUS

Office (OLE) / .XLS

238.0 KB Created: 2020-11-20 17:59:00 Authoring application: Microsoft Excel
MD5: 2630facfc34c2f673ed8df90e6605c56 SHA-1: 2c462db9f695db91d9c61d961f8a7ddb48d62b57 SHA-256: 49638c7502de579d5d7afa8081710d51193fb91b96055283a3af8b28b4e0721e
148 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File

The critical heuristics OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN indicate the presence of an Excel 4.0 macro sheet with an Auto_Open entry that uses dangerous functions. The extracted XLM macro script reveals that it constructs a command to download and execute a file from 'http://45.15.143.142/fa.exe' using Net.WebClient. This indicates the sample's primary purpose is to act as a downloader for 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.
  • 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.
  • VBA project contains no executable statements low OLE_VBA_MACROS
    Document contains a VBA project, but extracted modules only contain attributes/options/comments and no executable statements.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
1597ff65d5f7861fa0c4d946c47073bb5d1cba74aa00f8a0cef00374b493ddf6		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 2263 bytes
macros.bas
fed365d3401536fb63e11d0a36cc7c35338c0a8c74a96fb254c46366ad6287cd		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 642 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.