Malicious PDF — malware analysis report

Static analysis result for SHA-256 1ca31ec1fd221b22…

MALICIOUS

PDF

83.5 KB Created: 2021-10-18 22:01:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 7dca9de1ad543d4864bdcdc52a08b55f SHA-1: b821693bc3f8c34a7cf031ca4165e53ddaedb66b SHA-256: 1ca31ec1fd221b22db010f329d55e2082c2c60daea2293c8004d74cecaad39e2
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains a large number of embedded URLs, many of which point to other PDF files hosted on various domains. Several heuristics indicate this is a link farm, with some links pointing to compromised CMS upload storage. The ClamAV detection and ML classifier strongly suggest malicious intent, likely related to phishing or SEO abuse.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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 http://memsports.com.br/admin/libs/ckeditor/ckfinder/files/30103144498.pdf In PDF document text
    • http://meimagedance.tw/ufiles/files/75400402470.pdfIn PDF document text
    • http://sjar-tech.com/uploadfile/file///2021101604592273.pdfIn PDF document text
    • https://mamotato.ro/userfiles/file/11997535394.pdfIn PDF document text
    • https://dmitrovka-zn.ru/admin/ckfinder/userfiles/files/47171866290.pdfIn PDF document text
    • https://bcm.es/files/galeria/files/kukufilupuvipolesukesib.pdfIn PDF document text
    • https://xosobacninh.vn/webroot/img/files/25191495992.pdfIn PDF document text
    • http://podwierzba.eu/ckfinder/userfiles/files/53822825388.pdfIn PDF document text
    • https://seerupit.dk/assens/file/vejosaku.pdfIn PDF document text
    • https://webbsoil.com/home/webb/public_html/ckfinder/userfiles/files/21725951599.pdfIn PDF document text
    • http://sz-frp.com/pic/20211006175554605.pdfIn PDF document text
    • http://sunwisechem.com/Uploadfiles/files/sefutuzasilorirafa.pdfIn PDF document text
    • https://baongochoa.com/upload/file/bewigekamalakukibovipibix.pdfIn PDF document text
    • http://www.mediacomriccione.it/wp-content/plugins/formcraft/file-upload/server/content/files/161692752b23f5---39650097523.pdfIn PDF document text
    • http://batistar.fr/userfiles/file/kikemow.pdfIn PDF document text
    • http://smartmedicaleg.com/wp-content/plugins/formcraft/file-upload/server/content/files/161657b85dca7a---pilivawuzodunefeg.pdfIn PDF document text
    • http://www.vitrierbxl.be/wp-content/plugins/formcraft/file-upload/server/content/files/1615017476b778---4254496384.pdfIn PDF document text
    • https://arihantgranites.in/wp-content/plugins/super-forms/uploads/php/files/f73cea0a46f34fcdc317732d0bc54ec6/18973452111.pdfIn PDF document text
    • http://www.altrus.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1615f0ae188225---fafavuroku.pdfIn PDF document text
    • http://ellenia3.eu/userfiles/files/kegepiwip.pdfIn PDF document text
    • http://thcsducthang.pgdbactuliem.edu.vn/ckfinder/userfiles/files/39783499028.pdfIn PDF document text
    • https://mwasafat.com/uploads/files/30301549335.pdfIn PDF document text
    • http://medianet2000.net/amm_prod/image_news_popup/file/tadiva.pdfIn PDF document text
    • http://dtyxbpzx.com/filespath/files/20211009043056.pdfIn PDF document text
    • http://feedproxy.google.com/~r/MbOu/~3/xPAns0MRe5M/uplcv?utm_term=cambridge+primary+science+activity+book+3+answers+pdfPDF link annotation
    • 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_off0000e34f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE34F 11616 bytes
SHA-256: b390c769f3f4f698275c76e07afd0526a02f05fe17469a58cce5e48aef3df785
font_01_sfnt_off0000fe9f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE9F 15952 bytes
SHA-256: 44727bb260a159756622e92fb6a028368261882c748eb530a7870dd861aec610
font_02_sfnt_off000127a1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x127A1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1