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

Static analysis result for SHA-256 0c83a3effad40d98…

MALICIOUS

Office (OLE) / .XLS

243.5 KB Created: 2020-09-14 21:28:14
MD5: e305faa66a8defa8667a143f2c096ff0 SHA-1: 9405d3c7646455bc291ec85833c8a9c83f045415 SHA-256: 0c83a3effad40d9863c573af2ea95862fc08a15277608e728dcdf385fd8eec48
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding. The macro sheet contains a reference to a URL that is likely used to download and execute a secondary payload. The presence of dangerous formula APIs like RUN further indicates malicious intent.

Heuristics 3

  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
ea5af3150e2145d69bcc4193c543e45c2ef3e3dfc0b01e4d431c1365aa8d2da6
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 23045 bytes