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

Static analysis result for SHA-256 ac75d8de6984d66e…

MALICIOUS

Office (OLE) / .XLSX

62.0 KB First seen: 2022-10-10
MD5: 167430ee892e34ad732915fae8e98c1c SHA-1: 55a5043c7b656d65ed4a2eb594b0ea8a6e18b429 SHA-256: ac75d8de6984d66ef42a4c17a902859d20502f4b58fd989a9b15d78a475fba10
202 Risk Score

Malware Insights

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

MITRE ATT&CK
T1204.002 Malicious File T1071.001 Web Protocols T1105 Ingress Tool Transfer

The file is an Office document encrypted with a default password, a common technique to hide malicious content. It exploits CVE-2017-0199, which allows it to load a remote document from the URL http://document_docs@104.168.32.131/uAAuUASDbjasduhuasduyuASHUDHUSADHUASDU/8....................................................1.doc. This indicates a downloader functionality, likely to fetch and execute a second-stage payload.

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://document_docs@104.168.32.131/uAAuUASDbjasduhuasduyuASHUDHUSADHUASDU/8....................................................1.doc