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

Static analysis result for SHA-256 5650d3dd6570086a…

MALICIOUS

Office (OLE) / .XLSX

310.3 KB
MD5: 89d94f413973ddb59c65e38cf7fca359 SHA-1: c1e276203c11b61e3d290044120f050502214a4f SHA-256: 5650d3dd6570086acd866ef42a8ff6505db7e6b1d32a46b094aaa5dc87a45aea
180 Risk Score

Malware Insights

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

The sample is an encrypted Excel spreadsheet that contains an embedded Equation Editor OLE object, a known exploit carrier. The encryption and malformed structure indicate it is designed to evade static analysis and deliver a malicious payload. The presence of the Equation Editor OLE object strongly suggests exploitation of a vulnerability within that component.

Heuristics 5

  • 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.
  • Encrypted Office package with CFB FAT corruption critical OLE_ENCRYPTED_AND_MALFORMED
    Encrypted-package shape co-occurs with FAT-chain corruption — the documented combined evasion form.
  • 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 document is password-encrypted medium OFFICE_ENCRYPTED_PACKAGE
    OLE container holds MS-OFFCRYPTO encrypted package (Standard Encryption (Office 2007, AES)).
  • 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.