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

Static analysis result for SHA-256 6369f4162e2b6b08…

MALICIOUS

Office (OOXML) / .XLSX

763.0 KB Created: 2022-05-16 17:34:45 UTC Authoring application: Microsoft Excel 16.0300 First seen: 2023-01-30
MD5: 150e0362428410e9ed63d2b618833d80 SHA-1: 7f791d896eddcad760134e2e432c3c23d80f8a06 SHA-256: 6369f4162e2b6b088b9211305a039d77bba5d50750512446ce8e481f787c040c
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.002 Malicious File

The sample is an Excel file containing an embedded OLE object, specifically an Equation Editor object. Heuristics indicate this object carries a payload-like Ole10Native stream with an anomalous header and size discrepancy, suggesting it's designed to deliver malicious content. ClamAV detection confirms this, identifying it as 'Xls.Downloader.Trojan-aa0b8f388d8573cd-aa0b8f388d8573cd-9950439-0'. The presence of these indicators strongly suggests a downloader trojan attempting to execute a second-stage payload.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Embedded OLE object xl/embeddings/tQw0GXCj.tD 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
7583b022934d2c7284471acda0b577f0d7efae4f981a1e50712a05845929d358		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/tQw0GXCj.tD 888320 bytes
ooxml_oleobject_00_ole10native_00.bin
846a5bf016dc39340cf0c08620816c5422cda37c2f94f94f64d148c606cb574a		 ole-package OOXML xl/embeddings/tQw0GXCj.tD Ole10Native stream: OlE10NAtIve 879069 bytes
emf_00.emf
38f17a599ac5d645df3840bbb401710ef81573a747da20abbfc1b7d9a9273b58		 ooxml-emf OOXML EMF part: xl/media/image1.emf 169096 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.