Office (OLE) / .XLS malware analysis — malicious · 0c4034bf7b98e53f

MALICIOUS

Office (OLE) / .XLS

54.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel

MD5: 02283a3406bd2524e64a1c1c7c831b37 SHA-1: 6fa3b72df62ba1087920d0f537dae44dbb1c97b2 SHA-256: 0c4034bf7b98e53f49641428ac3413cf8407d1f10cf423fcce0970b2c38207d1

300 Risk Score

Malware Insights

MITRE ATT&CK

T1566.001 Spearphishing Attachment T1059.005 Visual Basic T1105 Ingress Tool Transfer

The sample is an Excel 4.0 macro-enabled spreadsheet that uses a lure to trick the user into enabling macros. Once enabled, the VBA code executes the `tres` function, which calls `URLDownloadToFile` to download a file from one of the embedded URLs. The XLM macros also indicate an Auto_Open execution, further supporting the malicious intent. The downloaded file is then likely executed, leading to a second-stage infection.

Heuristics 7

Reference to URLDownloadToFile API critical SC_STR_URLDOWNLOAD

Reference to URLDownloadToFile API
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.
URLDownloadToFile in VBA critical OLE_VBA_DOWNLOAD

URLDownloadToFile in 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.
VBA macros detected medium OLE_VBA_MACROS

Document contains VBA macro code
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

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_macros.txt` `2a1c7329c4c8792c67abecd81ffa3d95e2243efca26ae8a7b4838634109595bd`	xlm-macro	oletools.olevba.extract_all_macros (XLM macro listing)	5046 bytes
`macros.bas` `aa55a18a3f33259e345c5e53649ac5f2f1d89d5667b734f6c8f841105e5741f2`	vba-macro	oletools.olevba.extract_macros (decoded VBA source)	1692 bytes

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