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

Static analysis result for SHA-256 1b496958300a2923…

MALICIOUS

Office (OOXML) / .XLSX

655.8 KB Created: 2019-11-27 09:20:57 UTC Authoring application: Microsoft Excel 12.0000
MD5: 6463b012efcf8e4ad74aaa9ad3e07921 SHA-1: d058330aa2b8db3e2d796d9ea5a85a62db4d9d77 SHA-256: 1b496958300a292394001bcf659e0e73ed84fe3fac0cfbddaf93360cb9b28644
140 Risk Score

Malware Insights

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

The sample is an Excel file containing an embedded OLE object, specifically identified as a malicious Equation Editor object. This object carries a payload-like Ole10Native stream with an anomalous size, strongly indicating exploitation of a vulnerability within the Equation Editor component. The presence of a NOP sled further suggests shellcode execution. The file likely serves as a delivery mechanism for a secondary exploit or payload.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/IujBK.02zO3J contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • NOP sled detected high SC_NOP_SLED
    Found 20+ consecutive 0x90 bytes
  • 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
e215d79b41cd8d11faad761149de38e5dc4816e6e77465d4f9b22e241142a2d2		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/IujBK.02zO3J 931328 bytes
ooxml_oleobject_00_ole10native_00.bin
da3dd37386fab1b1ce0fbb11e1ee6133de33e297e27fbcdc9ea8682b762c2453		 ole-package OOXML xl/embeddings/IujBK.02zO3J Ole10Native stream: oLe10NatIVE 921531 bytes

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