Malicious PDF — malware analysis report

Static analysis result for SHA-256 4e39f90bfaa034a0…

MALICIOUS

PDF

71.4 KB Created: 2021-10-04 05:10:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 77af8faa478560ff2b0fff7b631144e6 SHA-1: fe3e32f92d7b5ebcff3c1001403ac4bbbbc3ad8f SHA-256: 4e39f90bfaa034a03a070b67fe3937f42233a527dbfd9ed87594cdde65a563cf
156 Risk Score

Malware Insights

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

The PDF contains numerous external links, many pointing to compromised WordPress sites or disposable hosting, indicative of a link farm used for phishing or malware distribution. The ML classifier and ClamAV detection strongly suggest malicious intent. The document body is heavily obfuscated and appears to be non-readable content generated by wkhtmltopdf, further supporting the idea that the primary function is to host malicious links rather than present readable content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9916

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://pistant.ru/uplcv?utm_term=strictly+come+dancing+oti+mabuse
    • https://n-v-v.dk/userfiles/file/vitomegefewilekasa.pdf
    • http://www.uppld.org/wp-content/plugins/formcraft/file-upload/server/content/files/16140a4b186fcf---tusunas.pdf
    • http://maidichike.com/upload/files/35427671577.pdf
    • http://maximaviajes.com/FCKfiles/file/80419515909.pdf
    • http://enotecagaribaldi.it/userfiles/files/sefumawelepu.pdf
    • http://www.andreapondika.cz/file/burikuruxedizi.pdf
    • http://mijneigenlift.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1614ced6c4e94b---49551217729.pdf
    • https://searchlink.org/userfiles/file/loboxenajobanibol.pdf
    • http://huemin.com/fckeditor/userfiles/file/leveb.pdf
    • http://phongthuydotho.vn/upload/files/84252670490.pdf
    • http://condosworld.com/abisol1/userfiles/files/28257606908.pdf
    • http://www.kissdocs.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16156ccb4c7345---mowejovujalaluxu.pdf
    • https://hylyt.co/wp-content/plugins/super-forms/uploads/php/files/6afdf65abf4766324199417662886b47/serizetulenezebipego.pdf
    • http://vitalbafitnessclub.eu/userfiles/files/57847762988.pdf
    • http://186086.com/upload/files/fapegusaxedemubadupu.pdf
    • http://vinczeandlaszlo.com/upload/95703722971.pdf
    • http://anm-av.de/uploads/files/vimukafinenewegomis.pdf
    • http://www.urbanwaterways.info/files/degoxatujelujetuno.pdf
    • https://www.hit-education.com/wp-content/plugins/super-forms/uploads/php/files/rf2pt9m92aju4ij6i59569ug66/giguxegexok.pdf
    • http://biblioteka-belzec.pl/upload/files/55132578064.pdf
    • http://gemmacapitalgroup.com/foto/file/jogawojofamadapofejarab.pdf
    • http://maraulsan.com/ckfinder/userfiles/files/43038728341.pdf
    • http://szkolka-wiercioch.pl/files/file/xemimusuj.pdf
    • http://studiolegalebisantis.it/userfiles/files/magezexupolukonopibukopa.pdf
    • http://kevinmcallisterlaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/72247585366.pdf
    • http://showplus.ae/userfiles/files/58221122419.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b4a5.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xB4A5 16792 bytes
font_01_sfnt_off0000ccb7.bin
0fe492e654c683fcccdc7a698cde51ec4425a7f9c82e2ac780a4d4bb0658d22a
pdf-font-stream PDF embedded font (sfnt) at offset 0xCCB7 16368 bytes
font_02_sfnt_off0000f5cd.bin
8b6cc513207b595907bc6c0c4f6d00e963311b65dbaad25a3e9cf033b289c939
pdf-font-stream PDF embedded font (sfnt) at offset 0xF5CD 11140 bytes