Malicious PDF — malware analysis report

Static analysis result for SHA-256 cb740fa440e9747b…

MALICIOUS

PDF

81.0 KB Created: 2021-09-01 20:00:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: fafb418fd8e78727e8b9329b41775301 SHA-1: 7d69b6713c8af8a7c4dd897a9c679a2fe465fdf9 SHA-256: cb740fa440e9747babea921ec36f2f25fab2028c4520c15f051ad903eefc0fc6
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links to external websites, many of which are hosted on compromised WordPress installations or disposable domains, indicating a link farm or phishing lure. The ML classifier and ClamAV detection strongly suggest malicious intent. While no scripts were directly extracted, the PDF structure and heuristic firings point towards the distribution of malicious content via embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 7

  • 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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://syntellect.ru/Repository/file/valumubulikeponiduwosuwod.pdf In PDF document text
    • https://nabsangram.com/userfiles/file/3781900429.pdfIn PDF document text
    • http://quinta.cl/upload/files/bomojesaku.pdfIn PDF document text
    • http://patroha.hu/file/74521269774.pdfIn PDF document text
    • http://3q1p.com/upload/file/2106271027317500025rl5m4bnw95i.pdfIn PDF document text
    • https://massagetheory.ca/wp-content/plugins/super-forms/uploads/php/files/1b55f215249fd9a6041981bd0a0955d6/32734223942.pdfIn PDF document text
    • https://paloaltospeakerseries.com/wp-content/plugins/super-forms/uploads/php/files/8750ae4a6cc3f5010aeff49f9c88b814/xejilelasora.pdfIn PDF document text
    • http://amtusa.com/wp-content/plugins/formcraft/file-upload/server/content/files/16081d2601e61c---92027642208.pdfIn PDF document text
    • http://sklepjola.pl/userfiles/file/fokogonirokawedetobibirij.pdfIn PDF document text
    • https://utilitydiscount.com/wp-content/plugins/formcraft/file-upload/server/content/files/160871965e6006---12284838871.pdfIn PDF document text
    • http://multiseal.com.ph/wp-content/plugins/formcraft/file-upload/server/content/files/161203fe2ad3a3---57342922027.pdfIn PDF document text
    • http://www.mondzorgvesa-voorschoten.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1609c54fe8d631---faxikuxibosazarituwe.pdfIn PDF document text
    • http://trackeg.com/en/wp-content/plugins/formcraft/file-upload/server/content/files/1608798f3b37f4---49495992736.pdfIn PDF document text
    • http://www.sunarnuricomuisvealisverismerkezi.com/wp-content/plugins/super-forms/uploads/php/files/rsfhkenmssd3q3cvcivnc7d0s4/wodogodijejin.pdfIn PDF document text
    • http://viaterrestre.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160f40cc876207---10874121101.pdfIn PDF document text
    • http://www.argentum.com/wp-content/plugins/super-forms/uploads/php/files/qitf988q7n6vi100auus3u1ant/zamaduzerojun.pdfIn PDF document text
    • http://christembassydocklands.org/wp-content/plugins/super-forms/uploads/php/files/aa6b0aee5773aaf6533ab636126c7296/53910968925.pdfIn PDF document text
    • https://avenue102.com/uploads/file/nosojimafezinedejugefal.pdfIn PDF document text
    • http://wsm.hk/images/files/vunusejumoz.pdfIn PDF document text
    • http://kfnmdg.com/upfolder/e/files/20210828130409.pdfIn PDF document text
    • http://baanpowertrain.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608e08a0a4d38---34790507877.pdfIn PDF document text
    • http://lorofilmes.com/Uploads/ckfinder/userfiles/files/mifinifanalikazomebaloxu.pdfIn PDF document text
    • https://gbagencement.fr/uploads/file/givusefodezig.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/3CAf4wW3hvY/uplcv?utm_term=only+king+left+in+chessPDF 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_off0000db7c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB7C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f393.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF393 10464 bytes
SHA-256: 7af45ba825cc84032744e87d2d82d52804e14fce6042d426489f78db4d6c0879
font_02_sfnt_off00010b56.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10B56 16508 bytes
SHA-256: d693b2484871595b6287b57f236ccd5f2ba83ebb967a3a598d425dc38d5337c2

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