Malicious PDF — malware analysis report

Static analysis result for SHA-256 31cb1cb1cd36aa16…

MALICIOUS

PDF

86.4 KB Created: 2021-07-05 10:07:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2026-06-05
MD5: e293cb5d6e79fda1d9c087418d9529ab SHA-1: 9e417f980e9fe6f555660c6360c88d118695173d SHA-256: 31cb1cb1cd36aa16f27a926f5c38289baa86a3b88d327e2fe5d4ee057cd3a114
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm hosted on compromised WordPress uploads, with numerous distinct hosts and UTM parameters suggesting a phishing or malware distribution campaign. No scripts were extracted, but the PDF structure itself facilitates redirection to external URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

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://infrive.ru/uplcv?utm_term=in+what+order+to+watch+the+seven+deadly+sins PDF link annotation
    • https://pensiuneavlasin.ro/wp-content/plugins/super-forms/uploads/php/files/q2j5e9tefbb231d6eaqicsgi5k/41552024612.pdfIn PDF document text
    • https://appchecar.com/ckfinder/userfiles/files/77627420466.pdfIn PDF document text
    • http://topcudental.com/img/userfiles/files/kenavozovadotibaba.pdfIn PDF document text
    • https://cvenhancer.com/wp-content/plugins/super-forms/uploads/php/files/5ab1070867a1433ef1b6adccdae168ad/jejofadowufogakelovizol.pdfIn PDF document text
    • http://www.ebsjosepirosamaria.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c4acb443551---kumumizavexepaven.pdfIn PDF document text
    • http://www.socalgreatwhite.com/wp-content/plugins/formcraft/file-upload/server/content/files/16081f6d28fd74---jijowevazakimuvagixafoku.pdfIn PDF document text
    • https://hantverkarenisandby.se/UserFiles/files/zoteranapeti.pdfIn PDF document text
    • https://www.pal-kont.hu/wp-content/plugins/super-forms/uploads/php/files/e8ecc1e1b1452b3901243f8cb7f16d7d/17994119036.pdfIn PDF document text
    • http://ckrestaurantgroup.com/ckfinder/userfiles/files/mureti.pdfIn PDF document text
    • https://www.varisistanbul.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607fe6c8666e4---situteri.pdfIn PDF document text
    • https://totalyoumovement.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607e7f5f54d9b---62756717721.pdfIn PDF document text
    • https://allmassage.net/upload/file/20210508174624.pdfIn PDF document text
    • https://www.inkfactory.pk/wp-content/plugins/formcraft/file-upload/server/content/files/1608423cdb7e04---vufowulakuwebaguvigirigo.pdfIn PDF document text
    • https://atlanthealth.com/wp-content/plugins/super-forms/uploads/php/files/7da777ddf362e4c85d4bc2598a867986/tedoralovimaje.pdfIn PDF document text
    • https://study-go.info/wp-content/plugins/super-forms/uploads/php/files/55de813cb9a70e12f24ddf62794095c7/jiwaro.pdfIn PDF document text
    • http://schokobrunnen.com/idata/nokevorasikibugikesotas.pdfIn PDF document text
    • https://hkbca.org/UploadFiles/file/20210526170353190.pdfIn PDF document text
    • http://www.absolutecateringla.com/wp-content/plugins/formcraft/file-upload/server/content/files/160870b7c055ec---63228758768.pdfIn PDF document text
    • https://engravestone.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607b184f25cce---24402734506.pdfIn PDF document text
    • https://nadinerogger.ch/userfiles/files/46107100891.pdfIn PDF document text
    • http://www.microsinusectomi.com/wp-content/plugins/formcraft/file-upload/server/content/files/16075425b85d81---2719933996.pdfIn PDF document text
    • http://www.sg-callenberg.de/wp-content/plugins/formcraft/file-upload/server/content/files/16073f7e89f360---58243911434.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_off0000ed50.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED50 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010567.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10567 10684 bytes
SHA-256: b869fd475d7a1d02bb8870d00587ccad433698c70d75cb5baa2795b91327e60a
font_02_sfnt_off00011dde.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11DDE 17648 bytes
SHA-256: 8493220d55d80821c44e93bc1db0864852f4078afef6e13b8fd2a5c4c70d2c0b

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