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

Static analysis result for SHA-256 34af58f335471b4b…

MALICIOUS

Office (OLE) / .XLSX

942.5 KB
MD5: 42ffa1de50be92d60b689aab661df047 SHA-1: d877e81aeec8b2ddc2efec4c5da48a9d405e929e SHA-256: 34af58f335471b4b04ae50daf64d5e109ce47795dcd3f5b460b10e2ffff0e458
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Phishing: Spearphishing Attachment

The sample is an encrypted OOXML file that contains an Equation Editor OLE object. This object carries a payload-like Ole10Native stream, indicating it is likely used to exploit a vulnerability in the Equation Editor for initial execution. No specific family could be identified, and no external IOCs were extracted.

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.