Office (OOXML) / .XLSX malware analysis — malicious · 802bed18401c2778

MALICIOUS

Office (OOXML) / .XLSX

703.1 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 12.0000

MD5: 5fd60dfeb9fec3727af2d0d16a2a4a92 SHA-1: c7cbc21b8ba38cd2bc085ceb9065a90210ad6929 SHA-256: 802bed18401c2778368ee8936dbe3d505c80dbaf4e2633298b42c9216e05e873

128 Risk Score

Malware Insights

MITRE ATT&CK

T1566.002 Spearphishing Attachment T1204.002 Malicious File

The file is an OOXML document containing an embedded OLE object, specifically identified as an Equation Editor. High-severity heuristics indicate that this object carries a payload-like stream with an anomalous header and a significantly larger declared size than its actual stream size, suggesting an attempt to exploit a vulnerability. The document also contains lures related to invoices and callback phishing, further supporting a malicious intent.

Heuristics 5

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/FsKqrbk.6loWv 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
Callback phishing phone lure medium SE_CALLBACK_LURE

Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns
Fake invoice / payment lure low SE_INVOICE_LURE

Document contains invoice or payment language paired with an action verb — useful context when combined with link, macro, or attachment indicators

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`ooxml_oleobject_00.bin` `54a01d151b4a3a77b1872a4e787bd687b566276c61cc6a6ca8f77860aeb69ade`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/FsKqrbk.6loWv	923648 bytes
`ooxml_oleobject_00_ole10native_00.bin` `a976dea94896e8ac90b53a239e0d138ea6a98d4c28c3e631492a74cb335cf302`	ole-package	OOXML xl/embeddings/FsKqrbk.6loWv Ole10Native stream: olE10NaTIVe	913479 bytes

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