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

Static analysis result for SHA-256 b24e61853d962948…

MALICIOUS

Office (OOXML) / .XLSX

867.5 KB Created: 2022-05-16 17:34:45 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2022-06-09
MD5: 739b884f3f6b7ef31d7de5d13bcda9d9 SHA-1: 0d351b5ac1e0f032c2ce7cd8b02a02ea9a6c85ef SHA-256: b24e61853d962948d97e9ba192b054e269fcfc10a4f1009b572b09c67f54ecad
160 Risk Score

Malware Insights

MITRE ATT&CK
T1559.001 Component Object Model Hijacking

The XLSX file contains an embedded OLE object identified as an Equation Editor. This object exhibits an anomaly where the Ole10Native stream is significantly larger than expected and carries a payload-like structure. ClamAV detection confirms this as a downloader Trojan. The presence of the Equation Editor OLE object and the anomalous Ole10Native stream strongly indicate its use for delivering a malicious payload.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/hROj1VR.oASGmZd contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • ClamAV: Xls.Downloader.Trojan-aa0b8f388d8573cd-aa0b8f388d8573cd-9950439-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Trojan-aa0b8f388d8573cd-aa0b8f388d8573cd-9950439-0
  • 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin
b9e2979ce7b4b10381d5015b2938a276f3a63ad7e5c165f27fd37e5111cd170b		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/hROj1VR.oASGmZd 999424 bytes
ooxml_oleobject_00_ole10native_00.bin
8e8bd7bcdabeacfb931605123512b9fefcdefcd1ad27e38e1f8474a43db10ea9		 ole-package OOXML xl/embeddings/hROj1VR.oASGmZd Ole10Native stream: OlE10naTivE 989091 bytes
emf_00.emf
38f17a599ac5d645df3840bbb401710ef81573a747da20abbfc1b7d9a9273b58		 ooxml-emf OOXML EMF part: xl/media/image1.emf 169096 bytes

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