Malicious PDF — malware analysis report

Static analysis result for SHA-256 253535c406e5ea90…

MALICIOUS

PDF

91.2 KB Created: 2021-08-16 08:10:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 4cf5c43c0384c1b39c29afbc01be7b7b SHA-1: b9cb60015e3465932cded2e79e07493297f28acf SHA-256: 253535c406e5ea9093d7e4fd04911f5dd6d5a9bf45f8c4995ee933b9567781e3
204 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript and numerous links pointing to compromised WordPress sites, suggesting an attempt to host and distribute malicious content. The ClamAV detection and ML classifier strongly indicate malicious intent, likely to trick users into downloading further malware. The primary attack vector appears to be a link farm designed to lead users to malicious PDFs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9989

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
  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://opalbiosciences.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608893e363d19---mumaralerawunotepukalano.pdf
    • http://lab4050.com/upload/editor/file/65416802981.pdf
    • http://buren-kompanie.de/userfiles/files/88574598963.pdf
    • http://selfmadefilms.nl/userfiles/files/ribifitudujikikuz.pdf
    • http://pvsystreports.com/wp-content/plugins/super-forms/uploads/php/files/7pr5ld418q6gtcu1rapb63v1m0/wimumaxirovivuvanorov.pdf
    • https://intelean.com/wp-content/plugins/formcraft/file-upload/server/content/files/160aa91154e2c0---16182769249.pdf
    • https://chinatupai.com/web/js/ckfinder/userfiles/files/sujileb.pdf
    • https://legacydockandmarine.com/wp-content/plugins/super-forms/uploads/php/files/502613d62cccd6a3997834d045b38b38/44956586058.pdf
    • http://claudiodauelsberg.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1610d99563bb3b---68864585707.pdf
    • http://www.drop-lok.com/wp-content/plugins/formcraft/file-upload/server/content/files/16074a68dc3659---65945835783.pdf
    • http://paroissedementon.fr/upload/files/kutitox.pdf
    • http://alphabodysupplements.com/newerac2c/userfiles/file/ramozorof.pdf
    • https://medok18.ru/wp-content/plugins/super-forms/uploads/php/files/b2d340d64f7063a2c615ffdd8d63f2bb/57404603152.pdf
    • http://dollreunion2020.com/clients/4/43/4392dc7a9e9236654a628da0af121bbb/File/kojasadadikivorajexu.pdf
    • http://www.julitolaschools.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607e9a073b3a0---basofeselaxuniruge.pdf
    • http://fratellibeninca.com/images/file/xowumuguzikokofon.pdf
    • http://informerfitness.com/wp-content/plugins/super-forms/uploads/php/files/9fe91e7b161aaed6c438a9c97bf4e380/detufevinixodinukunu.pdf
    • http://kolaykanal.com/userfiles/files/koxed.pdf
    • http://www.christinemartin.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160ab958c6ef47---71495118961.pdf
    • https://charlesstreetvideo.com/userfiles/file/1239884390.pdf
    • http://citadelcaralarms.com/userfiles/file/16473992351.pdf
    • https://apronorte.org.br/ckfinder/userfiles/files/68669066584.pdf
    • https://bistakalikotenetwork.com/userfiles/file/dewipa.pdf
    • http://www.sunarnuricomuisvealisverismerkezi.com/wp-content/plugins/super-forms/uploads/php/files/63csjou25qha8jabt6r55jb282/76775994785.pdf
    • http://counterreaction.net/wp-content/plugins/formcraft/file-upload/server/content/files/1606f4c7903120---65331288784.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=%D1%81%D0%BF%D1%80%D0%B0%D0%B2%D0%BE%D1%87%D0%BD%D0%BE%D0%B5+%D0%BF%D0%BE%D1%81%D0%BE%D0%B1%D0%B8%D0%B5+%D0%BF%D0%BE+%D1%80%D1%83%D1%81%D1%81%D0%BA%D0%BE%D0%BC%D1%83+%D1%8F%D0%B7%D1%8B%D0%BA%D1%83+4+%D0%BA%D0%BB%D0%B0%D1%81%D1%81+%D1%83%D0%B7%D0%BE%D1%80%D0%BE%D0%B2%D0%B0+%D0%BD%D0%B5%D1%84%D0%B5%D0%B4%D0%BE%D0%B2%D0%B0+%D0%B3%D0%B4%D0%B7
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f196.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF196 16792 bytes
font_01_sfnt_off000109a8.bin
174b8c936986e70e061b39e02827383831704721045728d156bae735d2701453
pdf-font-stream PDF embedded font (sfnt) at offset 0x109A8 20960 bytes
font_02_sfnt_off00013e2e.bin
d066c8f16b676f78076acbc5a27d169f559e19805f6de2e1164d1570489eeb4a
pdf-font-stream PDF embedded font (sfnt) at offset 0x13E2E 11748 bytes