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

Static analysis result for SHA-256 f7703dea53175c27…

MALICIOUS

Office (OLE) / .XLS

376.0 KB Created: 2020-07-10 10:41:45 Authoring application: Microsoft Excel
MD5: 61cb6d8e8643ff9cd68ee72d073f43ed SHA-1: 5e4d354c2746363d13661694b1f1c983216529af SHA-256: f7703dea53175c27e1c3391a883b7311d192310c1c4d0fe8c510cdf6fa1ff3c8
140 Risk Score

Malware Insights

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

The sample is an Excel file containing Excel 4.0 macros, specifically an Auto_Open defined name that executes a dangerous formula (RUN). The macro appears to be attempting to construct a URL from concatenated strings, which is likely used to download and execute a second-stage payload. The reconstructed URL is "http://orgbrqrzc.kYKlIU iQTxn cwed,DsVLONaFAJEuyGBPWf".

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
775de64f4086a200d29fdb024bc2aa19b4c0586cea91789b8d115500492f5ccc		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 93733 bytes

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