Malicious PDF — malware analysis report

Static analysis result for SHA-256 81bdc0a7d91e4f59…

MALICIOUS

PDF

92.4 KB Created: 2021-09-14 02:49:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 9ae3eaf9a959ff1c268b21587f27e9c3 SHA-1: 008b34abf9a5c359b6537640fcddb668113b0ac1 SHA-256: 81bdc0a7d91e4f5983cd967db06e18d4b0bf1e8f8593d0b0eded811bf0d99687
156 Risk Score

Malware Insights

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

The file was detected by ClamAV as Pdf.Phishing.Trojan and flagged by an ML classifier, indicating malicious intent. It contains numerous embedded URLs pointing to compromised WordPress sites and other disposable hosting, suggesting it functions as a link farm to redirect users to malicious content. The presence of these links and the overall structure strongly suggest a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9968

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://crewmak.ru/uplcv?utm_term=hero+academia+the+movie+heroes+rising PDF link annotation
    • https://brylka-kfz.de/wp-content/plugins/formcraft/file-upload/server/content/files/1613746fd33ff8---10102626179.pdfIn PDF document text
    • http://vitalchurchesinstitute.com/files/file/38529725413.pdfIn PDF document text
    • http://bhavalaya.org/ckfinder/userfiles/files/34399272096.pdfIn PDF document text
    • http://ukwoodrecycling.com/userfiles/files/kunazawimotivomefe.pdfIn PDF document text
    • https://cryptoshift.be/anaeter_capital/siteadmin/userfiles/files/vonudexuvitimimabuk.pdfIn PDF document text
    • https://www.toptalentusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/16134bb8eb4504---34242578082.pdfIn PDF document text
    • https://balance-global.com/wp-content/plugins/super-forms/uploads/php/files/uadic2mnd6bu31m1kgs4iba6l0/nojun.pdfIn PDF document text
    • https://reha.bg/content/upload/file/98968261987.pdfIn PDF document text
    • http://elma-itc.ru/!upload/files/vejemegagerev.pdfIn PDF document text
    • https://kop-trans.pl/uploads/userfiles/files/32968044837.pdfIn PDF document text
    • https://1snrpaulista.com.br/ckfinder/userfiles/files/memuxof.pdfIn PDF document text
    • http://stagegator.scorchmark.com/stagegator/ckfinder/userfiles/files/gowokikebururipibuno.pdfIn PDF document text
    • http://shinies.ru/img/lib/file/todenuso.pdfIn PDF document text
    • https://mkart.it/uploads/file/fuwasefe.pdfIn PDF document text
    • http://www.stadion-zarya.ru/ckfinder/userfiles/files/pekuvemuxipirowom.pdfIn PDF document text
    • https://groupekineconcept.com/userfiles/file/bisawif.pdfIn PDF document text
    • https://mobile-translator.eu/app/webroot/media/files/gumidomemikelikagufuzew.pdfIn PDF document text
    • http://gld-lining.com/user_img/files/kuzefadikeropijane.pdfIn PDF document text
    • https://yp05.com/_UploadFile/Images/file/19036413872.pdfIn PDF document text
    • https://yam-token.com/business_school/uploads/file/nedetubax.pdfIn PDF document text
    • https://santaclara.com/wysiwygfiles/file/betok.pdfIn PDF document text
    • https://sunsoftinfoway.net/ckfinder/userfiles/files/78256576862.pdfIn PDF document text
    • http://gmicropilotes.com/uploads/files/siguziwajumanidewew.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f475.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF475 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010c87.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C87 24600 bytes
SHA-256: 5a0e61a953e420cca43d51c5ef730d29135276433d0ff880a931cc3986832608
font_02_sfnt_off00014b4a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14B4A 10828 bytes
SHA-256: 22fdfbd378d69b556190e570fe7ba1a735d6a3bae1c2d817597ee9a549ae3976