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

Static analysis result for SHA-256 6583d461c94cee95…

MALICIOUS

Office (OOXML) / .XLSX

685.1 KB Created: 2021-06-11 10:05:56 UTC Authoring application: Microsoft Excel 14.0300
MD5: 96918bdaf41132ce7468777fea814d05 SHA-1: 6d83543f9b49c5627d6929cfc5413d1961da6e77 SHA-256: 6583d461c94cee95d8a6e1abf196eed880c21164843a60d2ccc9ed4875b8abc2
100 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The file is an Excel spreadsheet containing an embedded OLE object, specifically identified as an 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, strongly suggesting exploitation of a vulnerability like CVE-2017-11882. This technique is commonly used to execute arbitrary code, likely leading to the download and execution of a secondary malicious payload. The document body appears to be sales data, likely a lure to disguise the malicious embedded object.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/dGML.B6tKK 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
82a281f2f8b345d5197156b48bc6b1d3d772129d6060164b36c4d39fd3fedd43		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/dGML.B6tKK 969728 bytes
ooxml_oleobject_00_ole10native_00.bin
81399ac943240e6e97f3c1d8520de9b0288e25a37e1d2a6038caec3b27632b7b		 ole-package OOXML xl/embeddings/dGML.B6tKK Ole10Native stream: OLE10NATiVe 959780 bytes

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