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

Static analysis result for SHA-256 35ab1f2ff6b999c3…

MALICIOUS

Office (OLE) / .XLSX

1.17 MB
MD5: d2fb6c006fe4b81fae29c2b55435db93 SHA-1: 933a1198d1e26d32981b15280b26a1953086eb08 SHA-256: 35ab1f2ff6b999c3c80c2b0d2109275ad1f12092172dce5f49d48198e1f9b53a
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Phishing: Spearphishing Attachment

The sample is an OOXML file that is encrypted with a default password and contains an embedded Equation Editor OLE object. This object exhibits anomalies indicative of carrying a payload, suggesting it's designed to exploit a vulnerability within the Equation Editor component. No specific family could be identified, but the delivery mechanism points to a targeted attack.

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.