Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 d27d78bac17255ea…

MALICIOUS

Office (OOXML)

1.11 MB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 12.0000
MD5: 6a87b3ce5819ec9bba133b6cc483a4f2 SHA-1: 801d347b0223b006809c04d41c981a62f89fd5f7 SHA-256: d27d78bac17255eaf657172c72ab4eaeb5d0d0c13c231d7337bba5aae2006814
170 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The critical ClamAV detection and high-severity heuristics for an embedded Equation Editor OLE object with a payload-like stream strongly suggest this Excel file is malicious. The embedded object is a common vector for exploiting vulnerabilities to execute arbitrary code, likely to download and run a secondary payload.

Heuristics 6

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/oleObject1.bin contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • ClamAV: Xls.Downloader.af2fa5c5d0587870-9978799-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.af2fa5c5d0587870-9978799-0
  • Equation Editor object carries payload-like Ole10Native stream high OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY
    Embedded OLE object declares the Equation Editor CLSID but stores a large high-entropy Ole10Native stream with malformed package sizing. This is an exploit-shaped Equation/OLE payload container seen in malicious OOXML samples. It is not assigned to a specific CVE unless the MTEF/Equation Native primitive also matches.
  • Embedded OLE object medium OOXML_OLE_OBJECT
    Document contains an embedded OLE object
  • 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://www.day.com/dam/1.0
    • http://ns.adobe.com/xap/1.0/
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/tiff/1.0/

Extracted artifacts 7

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin
7f3c68f8a122e59f9d88df9c0e9bc2f7c8835914745ed7048d8e0852a95e7da3		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject2.bin 10240 bytes
ooxml_oleobject_00_ole10native_00.bin
59fb77315591a55324873430963abffa12244adc4996302250a87d8a758a5796		 ole-package OOXML xl/embeddings/oleObject2.bin Ole10Native stream: Ole10Native 8667 bytes
ooxml_oleobject_01.bin
219084b66f184a83ebb8556d070246b9f08d948f5cd1cb286e0e0d86363066ba		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 882688 bytes
ooxml_oleobject_01_ole10native_00.bin
b39976266cecd96598b5c3c0579efd503e77a97523fe8dd4c80f2256504b4d0a		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: Ole10naTiVE 873216 bytes
ooxml_oleobject_02.bin
dba06cc54ce8ba367a431eb7a88a587e74f781bde14f544828f3c289c7069a24		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/Microsoft_Office_Word_Macro-Enabled_Document1.docm 122516 bytes
emf_00.emf
5379e487f01fe37ae370c37387044f8cd6b839662e82ccf2904cb9705c42a443		 ooxml-emf OOXML EMF part: xl/media/image5.emf 7608 bytes
emf_01.emf
feefcba04dc09125532c8f8aeb2fe64ad22239d2bf4493060016777b6dc20366		 ooxml-emf OOXML EMF part: xl/media/image4.emf 648132 bytes

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