Office (OOXML) / .XLSX malware analysis — malicious · 1a519e292d8e3d24

MALICIOUS

Office (OOXML) / .XLSX

39.4 KB Created: 2020-04-29 13:43:05 UTC Authoring application: Microsoft Excel 16.0300

MD5: 68643d0d7a88fa9c2b065af0f9eef481 SHA-1: 64b56874b0cce20c303f02cf46282d3ea83c880c SHA-256: 1a519e292d8e3d240cf0766cf375e1c8787e399bed76b1bffbc4b8022238073b

128 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Service Execution: Service Execution T1059.001 PowerShell: PowerShell T1204.002 Malicious File: Malicious File

The sample is an Excel workbook containing numerous Excel 4.0 (XLM) macro sheets, which are rarely used in legitimate documents. The macros utilize dangerous functions like RUN and CALL, indicating an intent to execute arbitrary code. These functions are commonly used to download and execute second-stage payloads, making this a likely delivery mechanism for malware. No specific URLs or hashes were extracted, limiting direct IOCs.

Heuristics 5

Dangerous XLM formula APIs: RUN, CALL, HALT, 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.
Excel 4.0 macro sheet (25 sheet(s)) high 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.
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.
Hidden worksheet (hidden) low OOXML_HIDDEN_SHEET

Excel workbook contains 25 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.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

Extracted artifacts 25

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`xlm_sheet_00.xml` `d286de097658367aefac32ee6fe426b03b50af356f8b56094aaed39be307edbd`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet1.xml	61161 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 2 shell/COM execution token(s).
`xlm_sheet_01.xml` `65b79cee707f6fa1c0d70823822d5bc50ff29e88173e3f016ceeef2e1f8812a0`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet2.xml	14178 bytes
`xlm_sheet_02.xml` `e1c54efeec968a3f3e0d84cde63d2f281b3b69513c114488224528949c6e4e5e`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet3.xml	1086 bytes
`xlm_sheet_03.xml` `655ce68f03cbf8467570f2d5b34a09d18f1d71ff4581e91c4fb02d8570a32c91`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet4.xml	1086 bytes
`xlm_sheet_04.xml` `dd424a107b601f1c1e958a0b0c9fdde356e8f2d0bb3f7e23ad89935c4c0b3eb8`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet5.xml	1086 bytes
`xlm_sheet_05.xml` `f9c3245dfec094c1b319d3787877d63f2c60350351450dc54406cacbbc09c770`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet6.xml	1086 bytes
`xlm_sheet_06.xml` `b5650e1b07f123530860a48f6e29425a2fe4265e03a13bd0f4a35d217ea674c7`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet7.xml	1086 bytes
`xlm_sheet_07.xml` `dc987c55b54c7ed476e916f5e6e934c6c7019c1ffb21a0a04531b852c6de137e`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet8.xml	1086 bytes
`xlm_sheet_08.xml` `f7615562440760695a06c22d3ea8a91c6bb1d942a2bf9ee20e20619e5d5842b4`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet9.xml	1086 bytes
`xlm_sheet_09.xml` `f3b0dd89e4c1c057745d72e0111686db0653fc6fd461656a7152f2daaf4a3a80`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet10.xml	1086 bytes
`xlm_sheet_10.xml` `cb528f68314e114afc1d84a686461852e6ec312c63733e5c6fe582aeaa7ba511`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet11.xml	1086 bytes
`xlm_sheet_11.xml` `33c7e80c3a498da073dd40d6bfbdd6ee34389174da71b2bcb6fd6d68892c728b`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet12.xml	1086 bytes
`xlm_sheet_12.xml` `090ec3f817861f9fa7f46facd282a8ffe895a6af4899ff91dc0ce64750d80da7`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet13.xml	1086 bytes
`xlm_sheet_13.xml` `70f32ec8b72bfa9790f28d6bce044278538333c7fbe131b531f3f0ca5799a5b0`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet14.xml	1086 bytes
`xlm_sheet_14.xml` `f317be5ed376902f55c62470ed5bb9656bf2db804f935e81f3e4eee6223dc0f8`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet15.xml	1086 bytes
`xlm_sheet_15.xml` `c8b2934fa1d866c210635566c457bd1d025f0379d3aa747685ab6d54e263ceb2`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet19.xml	1086 bytes
`xlm_sheet_16.xml` `b8c2bdbe1c01f0c8c8f6f971469af359665ae387f94cd8d7788d91af12d2a2f4`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet20.xml	1086 bytes
`xlm_sheet_17.xml` `ce3fb63f2e4859d6b289867e2e2a66935106f280d00453714873d7b4eaf2b72b`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet21.xml	1086 bytes
`xlm_sheet_18.xml` `a0795cdb1a63bfc8f4474956255bd7c2e53062d516d3e745dd33dcb983440f91`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet22.xml	1086 bytes
`xlm_sheet_19.xml` `8fc52c26fb3c02b04889b8ee4869c72cc77d45d91f561bdac6063283ee770db7`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet23.xml	1086 bytes
`xlm_sheet_20.xml` `f50622b123778278b1f3c6eb62dae7dc566d2f4c52c8b34e4133325ae49e2716`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet24.xml	1086 bytes
`xlm_sheet_21.xml` `585ba29166ba13483203170cf655d5e65355734e3f91d4d548baa7f3489a0046`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet25.xml	1086 bytes
`xlm_sheet_22.xml` `6d3577dd7170bab3e6c38f07570decb132e1bab24825e32c8335f573c12d1fa7`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet16.xml	1086 bytes
`xlm_sheet_23.xml` `e0b0ccc526d4f20422bd1d1a5abeea84ad99dc3eb6e44479114118d470f22abe`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet18.xml	1086 bytes
`xlm_sheet_24.xml` `ef8c29394421aac2e0b88efc63ed8e987a976194a855a02d492c65b5236a2209`	xlm-macrosheet	OOXML XLM macro sheet: xl/macrosheets/sheet17.xml	1086 bytes

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