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

Static analysis result for SHA-256 a30a8873dd3c6939…

MALICIOUS

Office (OLE) / .XLS

76.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel
MD5: 785d3ecd020a7ec4959e4a676e8917b3 SHA-1: 8c2c5d92352e36184055f0045c1cf098f309c6b1 SHA-256: a30a8873dd3c69398abcfec41fdd5a4805761bf1c42887edadf2e3ce56ff0865
120 Risk Score

Malware Insights

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

The sample is an Excel 4.0 macro sheet with an Auto_Open macro, designed to execute automatically when the workbook is opened. It uses a lure to trick the user into enabling macros, impersonating a document signing service. The macro sheet contains references to `rundll32`, `DllRegisterServer`, `uRlMon`, and `RLDownloadToFileA`, indicating an attempt to download and execute a payload from one of the provided URLs. The presence of an Auto_Open macro and the lure strongly suggest a malicious downloader.

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.
  • 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.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • Document signing service impersonation lure medium SE_DOCUSIGN_LURE
    Document impersonates DocuSign, Adobe Sign, or a similar signing service in a signing-request context

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
28583d80fd380b8ce44feed33486a243b72383f3879b4322afeadd5f9732c23b
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 2255 bytes