Malicious PDF — malware analysis report

Static analysis result for SHA-256 185b8adfd47fbc23…

MALICIOUS

PDF

88.4 KB Created: 2021-08-30 12:06:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 609e754ee2661830dcf7c363f05a6a4e SHA-1: 165a747c82c05b71053e487029431a7d3ed91d8c SHA-256: 185b8adfd47fbc231613663e63030115d5555dc0f6a949e61a21c9f296eada36
156 Risk Score

Malware Insights

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

The file is identified as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It functions as a link farm, with numerous URLs pointing to various domains, many of which are likely compromised or disposable hosting. The presence of PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics further supports this, suggesting an attempt to manipulate search engine results or distribute malicious content through these links. The document body is heavily obfuscated and unreadable, providing no direct clues to its specific purpose beyond the link farm structure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://stijsr.com/userfiles/file/88486687444.pdf In PDF document text
    • https://nikosdimos.gr/userfiles/file/busipikekoza.pdfIn PDF document text
    • http://sanxuatbanthinghiem.org/app/webroot/uploads/files/57211561918.pdfIn PDF document text
    • https://lesfeesdelhetre.fr/upload/files/sukirivotomuk.pdfIn PDF document text
    • http://breakevenpoint.pl/uploads/editor/file/dabamalakiwijokeleze.pdfIn PDF document text
    • http://ciaooo.ru/uploades/userfiles/file/fusegemomamuduveg.pdfIn PDF document text
    • http://kocavietnam.com/upload/files/16141411169.pdfIn PDF document text
    • http://nutronicltd.com/userfiles/file/88524536769.pdfIn PDF document text
    • http://e-kva.ru/admin/ckfinder/userfiles/files/40178933264.pdfIn PDF document text
    • http://samurairamenbar.com/uploads/files/gododanuxanipow.pdfIn PDF document text
    • http://www.horakgolf.cz/ckfinder/userfiles/files/29863848560.pdfIn PDF document text
    • http://solarhomepage.ch/fckeditor/editor/images/file/tavibufusererimiwaru.pdfIn PDF document text
    • http://multi-accueil.fr/ressource/site-image/files/zulepejobovaxigukami.pdfIn PDF document text
    • http://aweibel.com/Photo/file/60767756580.pdfIn PDF document text
    • https://www.bouldersudbury.org/wp-content/plugins/formcraft/file-upload/server/content/files/160c4a6e71b668---zizeko.pdfIn PDF document text
    • https://connect.allianceflooring.net/wp-content/plugins/super-forms/uploads/php/files/bcd43e32e768e9bcb2d5b6391fd2728a/susubaf.pdfIn PDF document text
    • https://www.drserapkagan.com/wp-content/plugins/super-forms/uploads/php/files/t7lgq97ogqf177tik6rapgk89i/71733362900.pdfIn PDF document text
    • http://www.jesuseslaroca.org/wp-content/plugins/formcraft/file-upload/server/content/files/160e7d4cdb0baa---jepozok.pdfIn PDF document text
    • http://hanilkwanla.com/uploads/files/32701272949.pdfIn PDF document text
    • https://mission4recruitment.com/wp-content/plugins/formcraft/file-upload/server/content/files/16092637570e52---fuserub.pdfIn PDF document text
    • http://www.neslihanonur.com/wp-content/plugins/super-forms/uploads/php/files/709dd6c90b3936ef9f31aeb84a798b8a/2816300676.pdfIn PDF document text
    • http://forti.in/userfiles/file/60391842552.pdfIn PDF document text
    • http://safarang.com/basefile/files/96239979246.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BvfzZFkJO3s/uplcv?utm_term=edible+meat+offalPDF 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_off0000f190.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF190 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000109a7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x109A7 10264 bytes
SHA-256: 49837f600875163fded96a51c326a73aaff86b6f4bae2ad7698fd03346b79769
font_02_sfnt_off000120ad.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x120AD 19640 bytes
SHA-256: 2178ce312f9ea3f398b0fe8d3e4f782d4361fc50e360dcec5d8546817388fb35

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