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

Static analysis result for SHA-256 f2ce387dc7fca0e2…

MALICIOUS

Office (OLE) / .XLS

46.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-06-08
MD5: 119a38a73f6e3149c1d3db532ab826ee SHA-1: 94d8a89e3015e7a2764a254ac501e2f6ad197618 SHA-256: f2ce387dc7fca0e222d78155858865a04ef9ee1158027083155156c370558fad
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Service Execution: Visual Basic T1204.002 Malicious File: Malicious File

The critical heuristics OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN indicate the presence of an Excel 4.0 Auto_Open macro. This macro is designed to execute dangerous functions, specifically the RUN function, which is used to call external programs or URLs. The extracted URLs are likely part of a download chain for a second-stage payload. The macro's intent is to leverage the Auto_Open functionality to initiate the download and execution process.

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
f02d63843d495ffd8e99f1b7fe5f87a80501a758c9a61d8585f8be9700f36cb3
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7798 bytes