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

Static analysis result for SHA-256 58ca08b8c5558464…

MALICIOUS

Office (OLE) / .XLSX

1007.5 KB
MD5: 9a66ecbfd70181fff978a0c0801d89c1 SHA-1: 79fa46006893271c2ad549455a2ef378938637a4 SHA-256: 58ca08b8c55584645392741566f33d8f048f4936a569f0f3c2dd20cbfdafdb6f
140 Risk Score

Malware Insights

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

The sample is an encrypted OOXML file that utilizes a default password, a common technique for obfuscation. It contains embedded OLE objects, including an Equation Editor object, which is frequently used to deliver malicious payloads. The presence of an anomalous Ole10Native stream within the Equation Editor object strongly suggests it's designed to exploit vulnerabilities.

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.