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

Static analysis result for SHA-256 fca7f5cda93c9f47…

MALICIOUS

Office (OLE) / .XLSX

1.31 MB
MD5: b6d32254c5e3faa7fb26cccabddad2f4 SHA-1: abf474e378247ebeb3300de929a50d0996286c01 SHA-256: fca7f5cda93c9f473a6c3e9c3857d19d69c25835fd71b21d8b1354f78b102397
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566 Phishing T1204.002 Malicious File

The sample is an OOXML file that is encrypted with a default password and contains embedded OLE objects, specifically targeting the Equation Editor. This indicates it's likely an exploit carrier designed to leverage a vulnerability within the Equation Editor to execute a payload. No specific IOCs were extracted, but the attack pattern is clear.

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.