Office (OOXML) / .XLSM malware analysis — malicious · fd260864be7fd772

MALICIOUS

Office (OOXML) / .XLSM

113.2 KB Created: 2021-10-27 10:31:49 UTC Authoring application: Microsoft Excel 12.0000

MD5: fb1f72f39a57bad55a79610a9d046438 SHA-1: 223d18a5fe22171e6e3155e03cc6051483552f39 SHA-256: fd260864be7fd772d604b35b8a25c705a9215dcfb8818cdd3abbb4b58e7dee59

130 Risk Score

Malware Insights

MITRE ATT&CK

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

The sample is an XLSM file containing Excel 4.0 macros. These macros are designed to construct a path and filename, 'C:\ProgramData\assmAZqf\dqwok.dll', and then use the FOPEN, FWRITE, and FCLOSE functions to write a second-stage payload to that location. The macros also appear to construct and execute a file named 'dqwok.exe' from the same directory. The use of these dangerous XLM functions indicates a clear intent to download and execute a malicious payload.

Heuristics 4

Excel 4.0 macro sheet (1 sheet(s)) critical OOXML_XLM_MACROSHEET

Spreadsheet contains an Excel 4.0 (XLM) macro sheet — XLM was a major Office malware vector during 2020-2022 and evaded many VBA-focused controls before Microsoft tightened XLM defaults. Even legitimate XLM use is rare in modern workbooks.
Dangerous XLM formula APIs: FOPEN, FWRITE, FCLOSE, EXEC, RETURN critical OOXML_XLM_DANGEROUS_FN

Excel 4.0 macro sheet uses formula APIs that call directly into Win32 (=CALL/=EXEC/=REGISTER/=FORMULA). These are the primitives used to download payloads, write files, and start processes from an XLM macro without invoking VBA.
Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET

Excel workbook contains 1 hidden sheet(s) — hidden sheets are commonly used to conceal macro code, staging data, or intermediate payload construction
Embedded URL info EMBEDDED_URL

One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
URL http://schemas.openxmlformats.org/spreadsheetml/2006/main
- http://schemas.microsoft.com/office/excel/2006/main
- http://schemas.openxmlformats.org/officeDocument/2006/relationships

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.xml` `97f4a1370e38699e2072ac3f57b50cd2e292992d2cd5b30167d0184247604da1`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	5798 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.