Malicious Office (OOXML) / .XLSM — malware analysis report

Static analysis result for SHA-256 667443a0d8bd9497…

MALICIOUS

Office (OOXML) / .XLSM

122.8 KB Created: 2015-06-05 18:19:34 UTC Authoring application: Microsoft Excel 16.0300
MD5: ea162dd06fd6e24cb6254f63537bf14d SHA-1: b1188998292a73c6290c806890e5166ee6911ddc SHA-256: 667443a0d8bd9497dc7df561f029b6a59367e177f39004200f1347fff2b22627
250 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

The file contains critical heuristic firings indicating the presence of Excel 4.0 macros, including dangerous API calls like FORMULA, which are used to download payloads. The macros construct URLs such as "http://daferton.top/30fdh3fdh/update.dll" to fetch a second-stage payload. This indicates a downloader functionality, likely leading to further infection.

Heuristics 6

  • Excel 4.0 macro sheet (8 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.
  • Excel 4.0 Auto_Open defined name critical OOXML_XLM_AUTOOPEN_DEFINEDNAME
    Workbook defines _xlnm.Auto_Open or _xlnm.Auto_Close while containing an XLM macro sheet. This is the OOXML/XLSB auto-execution shape for Excel 4.0 macros.
  • Dangerous XLM formula APIs: FORMULA 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.
  • ClamAV: Xls.Downloader.GreenOffice01223-9937701-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.GreenOffice01223-9937701-0
  • Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET
    Excel workbook contains 11 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
    • http://schemas.openxmlformats.org/markup-compatibility/2006
    • http://schemas.microsoft.com/office/spreadsheetml/2009/9/ac
    • http://schemas.microsoft.com/office/spreadsheetml/2014/revision
    • http://schemas.microsoft.com/office/spreadsheetml/2015/revision2
    • http://schemas.microsoft.com/office/spreadsheetml/2016/revision3
    • http://schemas.microsoft.com/office/spreadsheetml/2016/revision6

Extracted artifacts 8

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_sheet_00.xml
951917452f51508fa7fcbfcbbc9f76ec839f945e614866e11f7a5f7783a1fffb
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/intlsheet1.xml 3864 bytes
xlm_sheet_01.xml
4077d5ba2f84cdff70678eb9149ba6dbb20869e45eb8e63b9b0fcdc47043ec5a
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet1.xml 1279 bytes
xlm_sheet_02.xml
347a45d58c3014652d1292cbf3343d054f1a993f8bbed8c27adb3b44f564bd5f
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet2.xml 1276 bytes
xlm_sheet_03.xml
a915ab0143c727ee0ef5570eb5bdaf594955dc963eeb8bec01eda574357378b8
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet3.xml 1276 bytes
xlm_sheet_04.xml
29536788abbc20742436b4dbe8445bce7ba727ab4c76176c3ac8a4664845e7e4
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet4.xml 1279 bytes
xlm_sheet_05.xml
3af8fd376a06d20ca4f9c51df77d57b89a3903d9a77bd2a99eae044bb2c2656c
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet5.xml 1279 bytes
xlm_sheet_06.xml
f3986bbddae4964981dc6dbfc11e3e44be66e4a0d3ab73d967e6c786ed5965f2
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet6.xml 1276 bytes
xlm_sheet_07.xml
1624f3e7ae6e74a27e3236325272c61f07a98f67f9e5836bf381e0b59e9b1789
xlm-macrosheet OOXML XLM macro sheet: xl/macrosheets/sheet7.xml 1279 bytes