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

Static analysis result for SHA-256 4d8ba73ed30f7bed…

MALICIOUS

Office (OOXML) / .XLSX

609.0 KB Created: 2020-01-08 16:45:10 UTC Authoring application: Microsoft Excel 12.0000
MD5: ed126806c975b9b3f791a2089d0563ff SHA-1: 9a38ba3494716a752a06bfe4d0ba2c599e9d37a1 SHA-256: 4d8ba73ed30f7beddaefb592e4e88cb5ffe2fbf2ae1c204b45ae86a41b3fe5db
100 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.002 Malicious File

The sample is an OOXML file containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. High-severity heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous header and a significantly larger declared inner size than the actual stream size. This strongly suggests exploitation of a known vulnerability within the Equation Editor component to execute arbitrary code.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/JK.H5qUYG contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • 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

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin
fdc4e642d616b1965e3353894c79fd6b112e5c9e4a3cc67f23cf9c15deca57ec		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/JK.H5qUYG 881152 bytes
ooxml_oleobject_00_ole10native_00.bin
cd11a701af1f060c3d2f03ec34b71601eb5764f649aba985c7cb20acffb2a843		 ole-package OOXML xl/embeddings/JK.H5qUYG Ole10Native stream: OLE10naTive 871598 bytes

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