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

Static analysis result for SHA-256 325d221ac6453505…

MALICIOUS

Office (OLE) / .XLSX

1.11 MB
MD5: 861a257c6357d7a22044a915927e237d SHA-1: f355a0fa9394ca71fc955b652716c96f7b308ac6 SHA-256: 325d221ac64535054b319e4e76c48bf40e3bc0b8b5dedd06fc6c89c44bf09f5d
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 embedded Equation Editor OLE object. This object exhibits anomalies in its Ole10Native stream, suggesting it is a carrier for a malicious payload. The presence of an Equation Editor OLE object is a strong indicator of exploit delivery, often used in conjunction with spearphishing attachments.

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.