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

Static analysis result for SHA-256 e3b4f91c44995be9…

MALICIOUS

Office (OLE) / .XLSX

1.21 MB
MD5: 978f15615315caedc0fed8dbe1db217f SHA-1: 269c83a67323f952d9be7e450ef5a546cd5e5c77 SHA-256: e3b4f91c44995be9ca6e0469d2ae3f593fac270eecabdf46c8b46b62d419d055
140 Risk Score

Malware Insights

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

The sample is an encrypted OOXML file that contains an Equation Editor OLE object. This object is known to be used to deliver exploits, and the 'OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY' heuristic indicates it carries a payload. The file is encrypted with a default password, suggesting it's intended to bypass basic security checks. No specific family could be identified, but the attack pattern is consistent with exploit delivery via a malicious Office document.

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.