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

Static analysis result for SHA-256 99f1ea61d020c4db…

MALICIOUS

Office (OLE) / .XLSX

2.46 MB
MD5: 55381e8ff5423a4b8124ef27d9eaed71 SHA-1: d0e1843beb92f3c7a7a5c38ac5c6d01e660d46f9 SHA-256: 99f1ea61d020c4db298f5296acc748d638e9d5dc22d6576ef16b06184f375494
100 Risk Score

Malware Insights

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

The file is an encrypted OOXML document, a common carrier for exploits. Heuristics indicate the presence of an Equation Editor OLE object, which is frequently exploited. The encryption with a default password further suggests malicious intent. No specific family is identifiable from the provided heuristics.

Heuristics 3

  • 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.
  • 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.