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

Static analysis result for SHA-256 4a4e64efc7a362ca…

MALICIOUS

Office (OLE) / .XLSX

20.8 KB First seen: 2022-03-11
MD5: 4715ca6aa9e03b2b5ebb15e51fa8c674 SHA-1: 252c105d69355e728896b6d48c271b0b9756276c SHA-256: 4a4e64efc7a362ca574f93f031b1298e396b24c0ae5801ae444b3a818462afee
200 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File T1059.001 PowerShell

The sample is an encrypted Office document that exploits CVE-2017-0199, a critical vulnerability allowing for remote code execution. The exploit carrier is located in xl/embeddings/oleObject1.bin and points to the URL https://2l.lv/Z. This indicates the document is designed to download and execute a second-stage payload from the specified remote location.

Heuristics 5

  • OLE2Link / URL Moniker → remote loader — CVE-2017-0199 critical CVE likely CVE_2017_0199
    Document contains an embedded OLE link object whose URL Moniker points to a remote URL. When the host file is opened, Office follows the link, downloads the URL, and processes the response based on its Content-Type (HTA -> mshta.exe, RTF → Word, etc.) — the documented CVE-2017-0199 primitive. The URL extension is not a reliable filter; servers can return different payloads to Office's user agent.
  • Encrypted Office package with CFB FAT corruption critical OLE_ENCRYPTED_AND_MALFORMED
    Encrypted-package shape co-occurs with FAT-chain corruption — the documented combined evasion form.
  • 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.
  • Office document is password-encrypted medium OFFICE_ENCRYPTED_PACKAGE
    OLE container holds MS-OFFCRYPTO encrypted package (Standard Encryption (Office 2007, AES)).
  • 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.