Malicious PDF — malware analysis report

Static analysis result for SHA-256 a51128fa5a46876e…

MALICIOUS

PDF

88.2 KB Created: 2021-08-11 16:09:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: f35be146b7109b69fb816f6d4bd1ea3c SHA-1: c83008ae05db1ce27becde1bd1e01c6c12ee6ee2 SHA-256: a51128fa5a46876e7aec747a12c7be9cca3e0a1d71e7d7720b3f2e46ee1652f3
236 Risk Score

Malware Insights

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

This PDF document is identified as malicious by ClamAV and an ML classifier, exhibiting characteristics of a social engineering attack. It employs a 'Browser Install Lure' and 'ClickFix' technique, instructing the user to install a fake browser update or extension, likely to facilitate the download and execution of a second-stage payload. The document also contains numerous links to compromised WordPress sites and disposable hosting, suggesting a link farm used for distributing malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

Heuristics 8

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • ClickFix social engineering attack high SE_CLICKFIX
    Document instructs the user to press Win+R or paste a command into a terminal — consistent with ClickFix attacks that bypass macro restrictions by tricking users into running malicious commands directly
  • Browser extension / update installation lure high SE_BROWSER_INSTALL_LURE
    Document tells the user to install a browser extension, plugin, viewer, or browser update to view content — a common social-engineering path for credential theft and malware installation
  • 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://medvor.ru/uplcv?utm_term=computer+engineering+course+pdf+download PDF link annotation
    • http://omniatel.it/wp-content/plugins/formcraft/file-upload/server/content/files/16076566e97350---bizavokejoninowitazeje.pdfIn PDF document text
    • http://willtorock.com/wp-content/plugins/formcraft/file-upload/server/content/files/16098f49f2d0c6---2609396430.pdfIn PDF document text
    • http://slp70.com/clients/873855/File/robemataximoxuruwelagagos.pdfIn PDF document text
    • https://www.tai.gr/wp-content/plugins/formcraft/file-upload/server/content/files/161095a8aad7c9---kopogixarefiloxiwe.pdfIn PDF document text
    • http://mouaumfb.com/wp-content/plugins/formcraft/file-upload/server/content/files/1610c47858c8fb---xoxurubapora.pdfIn PDF document text
    • http://www.siscard.com/wp-content/plugins/formcraft/file-upload/server/content/files/160df1ad846ba8---73458972036.pdfIn PDF document text
    • https://alatheir.com/atheirwsfiles/file/81136446061.pdfIn PDF document text
    • https://maloneslandscape.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606c87ef9673e---niromipozipezujikevubeta.pdfIn PDF document text
    • https://eduinfinite.com/wp-content/plugins/super-forms/uploads/php/files/17977c4eed91dfa2e8b09dd8dc7f1545/gizodofolatazojeruxeru.pdfIn PDF document text
    • https://traveletrust.com/basefile/traveletrustcom/files/nelepuwezuxiz.pdfIn PDF document text
    • https://www.gasserbush.com/wp-content/plugins/super-forms/uploads/php/files/e0f5269f75d1541ddece52e8b391c195/gisumirivuluj.pdfIn PDF document text
    • https://blackknowledge.com/wp-content/plugins/super-forms/uploads/php/files/ba621f359a8c5fba6fe2e9c3c1cbe570/98301473915.pdfIn PDF document text
    • http://fence-alarm.com/userfiles/files/33163461596.pdfIn PDF document text
    • https://maloneslandscape.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609801c88742b---68972359215.pdfIn PDF document text
    • https://kueapem.com/contents//files/mugorobabususovif.pdfIn PDF document text
    • https://littlelightnepal.org/userfiles/file/tetifizemavifutakevo.pdfIn PDF document text
    • https://www.hungryalex.com/wp-content/plugins/super-forms/uploads/php/files/2bd3e822720ca5a703f06b5db72de9c6/kadenogagizojajepevap.pdfIn PDF document text
    • http://turar-mussin.com/userfiles/File/wamirisumaketixa.pdfIn PDF document text
    • http://seventyfirstclassof69.com/clients/60772/File/zisuvimirikobudami.pdfIn PDF document text
    • http://xn----8sbpvg0afdbe.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/6djlilnrrkpi7okv8np0ve29e6/xoxego.pdfIn PDF document text
    • http://cohn-vossen.com/wp-content/plugins/formcraft/file-upload/server/content/files/160abb78851c43---sowemikiduxaka.pdfIn PDF document text
    • https://sinarwaja.com/account/files/banosizurow.pdfIn PDF document text
    • https://suemsas.com/wp-content/plugins/super-forms/uploads/php/files/pkv2r1adtujfmtpvs4d9hk4vl5/51667549169.pdfIn PDF document text
    • http://thehawthornnyc.com/wp-content/plugins/formcraft/file-upload/server/content/files/160771925da7fc---67376111604.pdfIn PDF document text
    • https://yziact.fr/wp-content/plugins/super-forms/uploads/php/files/6b2m7jfqh9muq6d1lufib6qano/lonazawapo.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_off0000f433.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF433 17048 bytes
SHA-256: 21b92103ed4c354e8e9d48abec90b29477e372645e801a7f0a7dd9b62048155d
font_01_sfnt_off0001207b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1207B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00013892.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13892 11180 bytes
SHA-256: 61d3761f4153db62ea8b2b403d5fae3e8cee32c3a90fb244bad2f39b31e2602d

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