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

Static analysis result for SHA-256 220db73fb64e12e0…

MALICIOUS

Office (OLE) / .XLS

76.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-05-23
MD5: 11176ae35f862e849600b7517ed25897 SHA-1: a8be8de57f309b6d801927a61f1797dd2259dd6e SHA-256: 220db73fb64e12e0c5af39d14b9b4c329f95c1fc6ef3a101690a20a7fd5addc8
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1204.002 Malicious File

The sample is an Excel file containing Excel 4.0 (XLM) macros, specifically an Auto_Open macro. This macro is designed to execute dangerous functions, including the RUN function, which is highly indicative of a downloader attempting to fetch and execute a second-stage payload from one of the embedded URLs. The presence of the Auto_Open macro and the use of dangerous functions strongly suggest 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
1253b9aedc963f347f6b0e8960abed4c25ca841ad10b30851eba81a4b10acde3
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7159 bytes