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

Static analysis result for SHA-256 d376547cb16cbfc6…

MALICIOUS

Office (OLE) / .XLSX

2.30 MB
MD5: 454e0170084563e99e9f5495834cb943 SHA-1: 65363e32c0f611a00c40794bb006c61da6b29ad2 SHA-256: d376547cb16cbfc646132b368082b3a419ca7e49a68174004aabb5cba31daa98
100 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 embedded OLE object, specifically identified as an Equation Editor. This combination strongly suggests it's an exploit carrier designed to leverage vulnerabilities within the Equation Editor when opened. The encryption with a default password further indicates an attempt to hinder analysis and disguise its malicious nature. While no specific IOCs like URLs or hashes were extracted, the presence of the Equation Editor OLE object is a high-confidence indicator of a malicious exploit delivery mechanism.

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.