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

Static analysis result for SHA-256 2fefb516bf7d8dbc…

MALICIOUS

Office (OOXML) / .XLSX

37.6 KB Created: 2021-04-28 14:40:56 UTC Authoring application: Microsoft Excel 15.0300
MD5: 79cc8c0593b05956f1d23ac078fcffca SHA-1: 017e34bea411d1e69802737d95a98af2d50b25f0 SHA-256: 2fefb516bf7d8dbc53e6f8c14bf64de30456b3db13bb90fbd3648af7c8baf956
100 Risk Score

Malware Insights

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

The sample is an Office Open XML (OOXML) XLSX file containing an embedded OLE object, specifically identified as an Equation Editor object. High-severity heuristics indicate the presence of CVE-2018-0798, an anomaly within the Equation Editor's native stream, which is a known vulnerability exploited for arbitrary code execution. This suggests the file is designed to leverage this vulnerability to execute a secondary payload.

Heuristics 3

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/oleObject1.bin contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • CVE-2018-0798 — anomalous Equation Editor native stream high CVE likely CVE_2018_0798_EQUATION_NATIVE_ANOMALY
    Embedded Equation Editor OLE data contains anomalous native stream bytes consistent with a CVE-2018-0798-style Equation Editor exploit. This is treated as likely CVE evidence because the Equation object is malformed and payload-like, but it does not match the exact public matrix-overflow byte signature.
  • 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
1e37eda9bf936832c045d56f317e89878b0041b2aa5cefac52d8d3af05163545		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 4096 bytes
ooxml_oleobject_00_ole10native_00.bin
39164b19263825c772dfbf9e7b49eaee18d7c650aeeaefc94cf1d2876675dfce		 ole-package OOXML xl/embeddings/oleObject1.bin Ole10Native stream: Ole10NAtIve 1772 bytes

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