Xls.Downloader.94c25b356b5a6cac-9978798-0 — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 5118e8975a79e61a…

MALICIOUS

Office (OLE) / .XLSX

58.0 KB First seen: 2022-07-27
MD5: abead1fc0f90ecc0312d75717ba18987 SHA-1: efc8658d665fc1c34bd8fa6a8d7845d634f309f6 SHA-256: 5118e8975a79e61a79e61eb16dcad75ab96b378702cfceae2e68eeb862e68fda
202 Risk Score

Malware Insights

Xls.Downloader.94c25b356b5a6cac-9978798-0 · confidence 95%

MITRE ATT&CK
T1204 Malicious Link T1204.001 Malicious Link: User Execution T1059 Command and Scripting Interpreter T1059.001 Command and Scripting Interpreter: PowerShell T1071 Application Layer Protocol T1071.001 Application Layer Protocol: Web Protocols

The file is an encrypted Office document identified as a downloader by ClamAV. It exploits CVE-2017-0199 via an OLE2Link object to fetch a secondary DOCX file from the URL http://23.95.52.140/msoffice/doc6/doc6.docx. This indicates a likely multi-stage attack designed to deliver further malicious content.

Heuristics 6

  • 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.
  • ClamAV: Xls.Downloader.94c25b356b5a6cac-9978798-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.94c25b356b5a6cac-9978798-0
  • 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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://23.95.52.140/msoffice/doc6/doc6.docx