Malicious PDF — malware analysis report

Static analysis result for SHA-256 4f6b7dd3396f0c93…

MALICIOUS

PDF

81.6 KB Created: 2021-09-14 12:04:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 567109cce0692a749c26243449c67016 SHA-1: f738a7b82421466538224a2395067be398e91f82 SHA-256: 4f6b7dd3396f0c93d079db3ff81cc026567f1b6bad1bf28985a5bc27eb679b77
156 Risk Score

Malware Insights

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

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with many embedded URLs pointing to potentially compromised or disposable hosting. The document body is heavily obfuscated and appears to be non-readable content generated by wkhtmltopdf, suggesting the primary malicious function is through its embedded links rather than document content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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 http://baracenter.be/userfiles/file/54153347029.pdf In PDF document text
    • http://louisamerino.com/userfiles/file/17429340124.pdfIn PDF document text
    • http://krakow4you.pl/krakow/files/sofufekeneg.pdfIn PDF document text
    • https://www.dyna-tech.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1613319d6dc5f6---ridawugofipaxizemuzoxiwu.pdfIn PDF document text
    • https://bhiringisamsankalimandir.org/userfiles/file/fijizalinawaxijobo.pdfIn PDF document text
    • http://esistore.lu/userfiles/file/fafelerexos.pdfIn PDF document text
    • http://danchrisjewelry.com/userfiles/file/verupukikivo.pdfIn PDF document text
    • http://szybkieprawko.pl/szybkieprawko.pl/user/admin/fck/file/47945774289.pdfIn PDF document text
    • https://tdemo.order-pro.com/ckfinder/userfiles/files/ruwuxupage.pdfIn PDF document text
    • http://patronusalapitvany.hu/public_html/upload/bibemevexotume.pdfIn PDF document text
    • http://preiss.at/upload_files/files/sawomolexitowad.pdfIn PDF document text
    • http://tscyw.net/userfiles/file/20210912080647_819xri.pdfIn PDF document text
    • http://velkoobchod-man.eu/ckfinder/userfiles/files/36533356706.pdfIn PDF document text
    • https://xn--78-6kce7dfhb9dwb.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/10a2d7560a12eee12611f0bc07278402/liwetadunep.pdfIn PDF document text
    • http://inbiosa.eu/static/cfiles/files/3999449130.pdfIn PDF document text
    • https://www.paparazzirestaurant.com.au/wp-content/plugins/super-forms/uploads/php/files/bec9b711b5cb0a105fe2f72a6a9455dc/jisaberuzakafo.pdfIn PDF document text
    • http://www.motionmantra.com/userfiles/files/tumavafugajila.pdfIn PDF document text
    • http://iranjobex.com/cache/fck_files/file/46968802665.pdfIn PDF document text
    • https://okna-kursk.ru/page_edit/_samples/userfiles/files/75031799104.pdfIn PDF document text
    • http://filippodelvita.com/demo/userfiles/file/45808042299.pdfIn PDF document text
    • https://esperidiaogomes.com/userfiles/files/3896849100.pdfIn PDF document text
    • http://ranfeng.com/userfiles/file/2021-9///2021911151433895.pdfIn PDF document text
    • https://westcoastmovers.ca/wp-content/plugins/super-forms/uploads/php/files/np53iaceitpr3k96209pc9gk3p/tolominerurowimilelilegiz.pdfIn PDF document text
    • https://advicezone.org.uk/wp-content/plugins/super-forms/uploads/php/files/akjr89vs09scug0th02bvmn6sv/lomat.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/GLLx1DTH0VQ/uplcv?utm_term=14+letter+words+starting+with+sPDF 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_off0000daa4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDAA4 10644 bytes
SHA-256: d8533b4fe31b757f61817445645c2b9e97d12b948d2f03f8081eabd348dd94eb
font_01_sfnt_off0000f2ce.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2CE 17880 bytes
SHA-256: 834fda6490a3e075f06844cf41aa99eac2bab5124d52a339fc153f4d465860ea
font_02_sfnt_off00012102.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12102 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1