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

Static analysis result for SHA-256 3b0118ac6f868f30…

MALICIOUS

Office (OLE) / .XLSX

1.23 MB
MD5: ab318793cf1ee7a0a432c3075f7f1c46 SHA-1: 2ab71593386f24f550ca33f237349c3be15be31a SHA-256: 3b0118ac6f868f3025bb5fee7bc3ca56ac35b0dbdb4c96311ee541ecb3a72251
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.001 Malicious Link

The sample is an encrypted OOXML file that utilizes a default password, a common technique for obfuscating malicious content. It contains an Equation Editor OLE object, which is frequently used to deliver exploits. The presence of an 'ole10NaTIVE' stream within the Equation Editor object, with an anomalous header and a significant size discrepancy, strongly suggests it's a carrier for a malicious payload. This points towards an attack pattern involving a malicious attachment designed to exploit vulnerabilities via the embedded Equation Editor object.

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.