Malicious PDF — malware analysis report

Static analysis result for SHA-256 c4c899edd0a11010…

MALICIOUS

PDF

77.9 KB Created: 2021-09-27 07:58:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: e37855a177169489e3e7e16b8a5bb9f8 SHA-1: 34737c08eae778f45b1e98112af62dfdf416384c SHA-256: c4c899edd0a11010b7438910df35ac014175f718fcd3761021a84e9e773a26fe
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous embedded URLs pointing to various domains, many of which appear to be compromised or disposable hosting. The ML classifier strongly indicated maliciousness, and the heuristic firings suggest this PDF is part of a link farm designed to direct users to external content. No scripts were extracted, but the sheer volume of suspicious links points to a malicious intent, likely related to SEO poisoning or redirecting users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9946

Heuristics 5

  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • 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 https://nomylo.ru/uplcv?utm_term=major+muscle+group+of+the+upper+body PDF link annotation
    • http://contua.org/userfiles/file/fevut.pdfIn PDF document text
    • http://bwc.lt/i/88895746710.pdfIn PDF document text
    • http://erh-hu.com/userfiles/file/fixumufogerumipidike.pdfIn PDF document text
    • https://atarentacarburdur.com/userfiles/file/favadupeta.pdfIn PDF document text
    • https://tungafilm.com/dorceiys/ckfinder/userfiles/files/40391494980.pdfIn PDF document text
    • http://vistobrasil.net/uploads/file/denizinavofolozel.pdfIn PDF document text
    • http://adams-gold.ru/archive/image/file/38127436388.pdfIn PDF document text
    • https://www.olympusnorge.no/wp-content/plugins/super-forms/uploads/php/files/mnr1erosopkioqfvvsc61ft942/30650299799.pdfIn PDF document text
    • http://bibliotekaszamocin.pl/img/upload/files/74444112820.pdfIn PDF document text
    • http://winkeleninzundert.nl/uploadimages/files/sakoleludetasolode.pdfIn PDF document text
    • https://hostsolutions.ro/app/webroot/files/userfiles/files/71795812883.pdfIn PDF document text
    • http://sumtinathholidays.com/admin/uploadfiles/file/69688067010.pdfIn PDF document text
    • http://zgic.ru/!upload/files/wezerelilotunezawokol.pdfIn PDF document text
    • https://eyescare.vn/app/webroot/upload/ckfinder/files/kudetadirijeziseluzop.pdfIn PDF document text
    • https://sealordhotels.com/ckfinder/userfiles/files/gufawi.pdfIn PDF document text
    • https://www.etbsupplies.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613008201cfd7---81878244130.pdfIn PDF document text
    • https://klingende-zeder.de/wp-content/plugins/formcraft/file-upload/server/content/files/161328eb44559e---91854798165.pdfIn PDF document text
    • http://www.pantonerestauri.com/ckfinder/userfiles/files/wulerekozufutelaxezij.pdfIn PDF document text
    • http://oticonshop.com/ckfinder/userfiles/files/gazuta.pdfIn PDF document text
    • https://gkatsov.com/userfiles/file/podimijirijajinufusedebu.pdfIn PDF document text
    • http://ersenergy.com/UserFiles/file/27457235324.pdfIn PDF document text
    • https://www.uflo.edu.ar/ckfinder/archivos/documentos/21285098850.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000afa2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAFA2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000c7b9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC7B9 11348 bytes
SHA-256: 360eccef5d189001d85ede340f128d82f0186bed8808b4186782647a0a2d4383
font_02_sfnt_off0000e219.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE219 16472 bytes
SHA-256: f648859687efeb1ac98081f4a18a359a166783cfee784bee6ff437361f50824f
font_03_sfnt_off00010c20.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C20 18572 bytes
SHA-256: f9a730db3b30a015358227f1574e456bbe30e4af4960d42f6210093968d8f8c5