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

Static analysis result for SHA-256 5f4e4fbde7ed003d…

MALICIOUS

Office (OOXML) / .XLSX

642.6 KB Created: 2019-11-27 09:20:57 UTC Authoring application: Microsoft Excel 12.0000
MD5: 99feb78ab55c66b871d8998b20528b61 SHA-1: 1c96f08e92401f2396ad0b074ca55049a773e4e0 SHA-256: 5f4e4fbde7ed003dc34954ee301977f697de1cd2d52beafd898023797ab47255
100 Risk Score

Malware Insights

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

The sample is an Excel document containing an embedded OLE object, specifically identified as a Microsoft Equation Editor object. Heuristics indicate that this Equation Editor object carries a payload-like Ole10Native stream with an anomalous size, strongly suggesting exploitation of a known vulnerability (CVE-2017-11882) to achieve arbitrary code execution. The document body content appears to be a list of parts or inventory items, likely a lure to disguise the malicious embedded object. The primary attack vector is likely spearphishing, with the embedded exploit serving as the execution mechanism.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/bG1.Ac2VNh 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
6b2275e2e914484b94d3c33b0bd18251624ea4220f5bc337eb913be7bdfedd1e		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/bG1.Ac2VNh 967168 bytes
ooxml_oleobject_00_ole10native_00.bin
8dd68c32513d5c1efc971a0efcd21d54abea852abb49a12c85c9529549c18107		 ole-package OOXML xl/embeddings/bG1.Ac2VNh Ole10Native stream: ole10nativE 957277 bytes

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