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

Static analysis result for SHA-256 a452c3adad157b09…

MALICIOUS

Office (OLE) / .XLSX

1.20 MB
MD5: bcddd6487a0e1ef2e7d32cc59be48383 SHA-1: caa9a616139af3ffa83f19f71e5a723380ca405a SHA-256: a452c3adad157b098a28aea1626cff66e0c97de0a34c429de85d3fd6c0faaa72
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an encrypted OOXML file that contains an Equation Editor OLE object, a known exploit carrier. The OLE object exhibits anomalies suggesting it contains a payload, and the presence of an embedded DOCM file further indicates malicious intent. The exploitation of the Equation Editor OLE object is a common technique for delivering second-stage malware.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Default-encrypted OOXML 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.
  • Default-encrypted OOXML exploit carrier layout high OOXML_ENCRYPTED_EXPLOIT_CARRIER_SHAPE
    Default-password encrypted OOXML package contains embedded OLE object parts and additional activation/decoy parts. This layout is common in malicious Excel exploit delivery and requires inspecting the decrypted package.
  • Equation Editor object carries payload-like Ole10Native stream high OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY
    Default-encrypted OOXML embedded OLE object declares the Equation Editor CLSID but stores a large high-entropy Ole10Native stream with malformed package sizing. This is exploit-shaped Equation/OLE payload evidence.
  • Office OOXML encrypted with default VelvetSweatshop password medium OFFICE_DEFAULT_PASSWORD_ENCRYPTED_OOXML
    OLE EncryptedPackage decrypts with Excel's built-in VelvetSweatshop password. Office opens this transparently, and malware uses it to hide OOXML exploit parts from scanners that only inspect the outer OLE container.