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

Static analysis result for SHA-256 a6b6080b4146a109…

MALICIOUS

Office (OLE) / .XLSX

1.16 MB
MD5: cdc3d6e1f6e355271d47711b561d5a96 SHA-1: 2e73dc71b3995db85f866e1d014a8f2feb1894fd SHA-256: a6b6080b4146a109d9c2bbb3e3bf4dd511b37deae0c3f333922e3e44a91ec74f
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 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 an embedded Equation Editor OLE object, which is frequently used to deliver malicious payloads. The anomaly detected in the Ole10Native stream within the Equation Editor object suggests it's designed to carry an exploit, likely targeting vulnerabilities associated with Equation Editor.

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.