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

Static analysis result for SHA-256 a95a1c04fce6b30c…

MALICIOUS

Office (OLE) / .XLSX

1.17 MB
MD5: 556ed2559ab158f47739dc1426dbb77b SHA-1: cb10bbb7a621ec6b33ff9a9594b109bf6d6abe29 SHA-256: a95a1c04fce6b30cf856d6702e46cc99a74079c6c79575ffb6c2015f707ec9bf
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566 Phishing T1204.001 Malicious Link: Malicious Link T1566.001 Phishing: Spearphishing Attachment T1566.002 Phishing: Spearphishing via Service

The sample is an encrypted OOXML file that contains an Equation Editor OLE object. This object exhibits anomalies in its Ole10Native stream, suggesting it carries a malicious payload. The presence of the Equation Editor OLE object is a strong indicator of exploitation, likely for delivering a second-stage payload.

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.