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

Static analysis result for SHA-256 3e4c13d0f2d18814…

MALICIOUS

Office (OLE) / .XLSX

1.17 MB
MD5: a455c811a6ea1402fb63e8294462c0e8 SHA-1: 531888feb5cc80aa555dcf84ac7e0183f4a905d8 SHA-256: 3e4c13d0f2d18814ad9c17790a062b0bc4157884e8a89daabee3c7670b64f64e
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 Equation Editor OLE object. This object carries a payload-like Ole10Native stream, indicating it is likely used to exploit a vulnerability in the Equation Editor for initial execution. No specific family could be identified, but the delivery mechanism is consistent with targeted attacks.

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.