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

Static analysis result for SHA-256 56839f1221dffba3…

MALICIOUS

Office (OLE) / .XLSX

1.20 MB
MD5: 35d7090f97fb9d73cc026c87b6f233e6 SHA-1: b2e18c7411a925f72559b1cb1c1d8f6686ca59c6 SHA-256: 56839f1221dffba3e134d4a0d4fcced6ed37304af230e721576f0635152668a4
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an OOXML file encrypted with a default password, a common technique to evade static analysis. It contains embedded OLE objects, specifically identified as Equation Editor objects, which are frequently used to deliver exploits. The anomaly in the Ole10Native stream size suggests it's likely carrying a malicious payload, although the exact nature of the payload cannot be determined from the provided heuristics.

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.