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

Static analysis result for SHA-256 1b48e7513cdc3303…

MALICIOUS

Office (OLE) / .XLSX

624.5 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel First seen: 2023-08-15
MD5: 6827a70838eef599cbca7b072ed186d2 SHA-1: a8bab359dde748e8e7574ffaa4a720df0a2dcd9d SHA-256: 1b48e7513cdc33036bc7172bcefbc8b197bb698ca51066d28f15c8478c9592fd
194 Risk Score

Malware Insights

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

MITRE ATT&CK
T1204.002 Malicious File T1059.005 Visual Basic

The file is identified as malicious by ClamAV and exhibits critical heuristic firings for CVE-2017-0199, indicating it attempts to exploit this vulnerability. The embedded URL is used to download a secondary payload, likely a document disguised as a PDF, which itself contains suspicious static findings. No VBA macros were extracted, but the presence of the CVE exploit and the embedded URL strongly suggests a downloader functionality.

Heuristics 7

  • 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.
  • Secondary embedded PDF body has suspicious static findings critical POLYGLOT_CHILD_PDF_STATIC_TRIAGE
    A valid PDF body was found at a nonzero offset inside another container and its carved contents matched PDF exploit or lure heuristics. This catches polyglots where the top-level magic routes to ZIP/OLE while a PDF reader or downstream parser opens the hidden PDF payload.
  • ClamAV: Xls.Downloader.94c25b356b5a6cac-9978798-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.94c25b356b5a6cac-9978798-0
  • VBA project contains no executable statements low OLE_VBA_MACROS
    Document contains a VBA project, but extracted modules only contain attributes/options/comments and no executable statements.
  • PDF paints image(s) but contains no text operators info PDF_IMAGE_ONLY_LURE
    PDF has 2 image XObject(s) and the content stream contains no text-emitting operators (BT/ET, Tj, TJ, ', ") in either raw bytes or decompressed streams — this is the screenshot-as-PDF pattern used to bypass text-based scanners and to deliver instructions purely through rendered pixels. It is informational unless paired with invisible links or risky URI context.
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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://104.168.46.25/RRTC/000OOO0OO0O0O0OO00000OO000000000000%23%23%23%23%23%23%23%23%23%23%23%23%23%23000000000000000000%23%23%23%23%23%23%23%23%23%23%23%23%23%2300000000000.DOC
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/pdf/1.3/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/xap/1.0/mm/

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
7f506327609c082af1cd37dde23bc2c71a000f7d1ef530b6abb66775040a7673
vba-macro oletools.olevba.extract_macros (decoded VBA source) 1206 bytes
polyglot_child_pdf_off0002ca00.pdf
36b93ad9cbd00e2c3475114ab94d7b444ed2ad41ef84828927ec06e9030e1345
polyglot-child-pdf Secondary PDF body inside ole container at offset 0x2CA00 456704 bytes
polyglot_child_pdf_off0003dc00.pdf
1cf89b1ce1ad61546ea0b9502efc6446f6d71b99485eb47444c4622cc376fab3
polyglot-child-pdf Secondary PDF body inside ole container at offset 0x3DC00 386560 bytes