Office (OLE) / .XLS malware analysis — malicious · ae5a246bd9082ec8

MALICIOUS

Office (OLE) / .XLS

205.0 KB Created: 2021-08-18 21:45:08 Authoring application: Microsoft Excel

MD5: 7288645954bda63f57cbf5e407a1e173 SHA-1: 82f83f76be4d9683e4f7ff1689b4bbec7d9f1f31 SHA-256: ae5a246bd9082ec804f233367f9b33eb062d2f3a9b3ebc32480cd64372a21c4a

200 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

The Excel 4.0 macro sheet contains an Auto_Open macro that executes a command. This command uses 'curl' to download a DLL from 'https://bizcomtech.com/rob122DzjsdFA.dll' and saves it as 'c:\users\public\cdnupdater.png'. The macro then checks if the file exists and proceeds with execution. The use of Auto_Open and dangerous function APIs indicates a malicious intent to download and run a second-stage payload.

Heuristics 5

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.
LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND

Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
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.
Suspicious extracted artifact medium EXTRACTED_FILE_STATIC_TRIAGE

One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_macros.txt` `2ae8799f732ae02478a8ebca8c6eb412a6d1e79f21fbacbcc8a880b099766c8d`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	3746 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 shell/COM execution token(s).

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