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

Static analysis result for SHA-256 33877c64ff03794b…

MALICIOUS

Office (OOXML) / .XLSX

646.4 KB Created: 2010-06-04 08:55:28 UTC Authoring application: Microsoft Excel 15.0300 First seen: 2023-08-09
MD5: aa767000909b63a93549edb44b6047e2 SHA-1: 1bf24730f2d268ddaadc90dd31d5811975fb206a SHA-256: 33877c64ff03794b51581b7014d85961c7d452a0cd911cfc7cb5a2f29d73fbf8
100 Risk Score

Malware Insights

MITRE ATT&CK
T1559.001 Component Object Model Hijacking T1204.002 Malicious File

The sample is an Office document 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 stream size. This strongly suggests the exploitation of a vulnerability within the Equation Editor to embed and execute a malicious payload. No scripts were extracted, and the document body appears to be a legitimate-looking invoice, indicating the exploit is likely the primary malicious function.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/3X4.lDqlaW 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
68745e792e0649996458202ec1f4477f01bba5fcbc5ee691b9f3d57712445c8c		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/3X4.lDqlaW 868352 bytes
ooxml_oleobject_00_ole10native_00.bin
d144f70dc9621be48918b584dbc8d54dd16d34fe81d9a869bbea0fc155365491		 ole-package OOXML xl/embeddings/3X4.lDqlaW Ole10Native stream: oLE10nATiVe 858649 bytes

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