Malicious PDF — malware analysis report

Static analysis result for SHA-256 c4b78e1c07569233…

MALICIOUS

PDF

82.8 KB Created: 2021-09-03 13:57:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: daa999ad3abfa64a6251bc84a18848fb SHA-1: 98ff58a01a0983f7ffd8125a81987a65fa56ff85 SHA-256: c4b78e1c075692336d5ea8d34079017da64f502e620c2adb888bd248e4ba67df
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file identified as malicious by ML classifiers and ClamAV. It contains numerous embedded URLs, many of which point to compromised WordPress sites or disposable hosting, suggesting a link farm or SEO poisoning tactic. The presence of external URI heuristics and the ML_NYX_PDF_MALICIOUS firing strongly indicate malicious intent, likely related to phishing or malware distribution via these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://chcial.ru/uplcv?utm_term=rationalizing+the+denominator+worksheet+with+answers PDF link annotation
    • http://xn--b1ahhafccpgkb2bxo.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/0225219097dc457e45912e433a99a9e9/31745905677.pdfIn PDF document text
    • https://bisnismedsos.com/userfiles/file/13362912294.pdfIn PDF document text
    • http://themultifold.com/wp-content/plugins/super-forms/uploads/php/files/ncqostiml05ac09p3ovol0pkk2/64764265126.pdfIn PDF document text
    • https://arerp.kr/data/file///99568396850.pdfIn PDF document text
    • http://sushikyototogo.com/uploads/files/57807919228.pdfIn PDF document text
    • https://estidevelopers.com/wp-content/plugins/super-forms/uploads/php/files/b31308e1a928ef734628ea28f75eefe3/kijugaseliwop.pdfIn PDF document text
    • https://campermagazine.tv/public/file/96332332235.pdfIn PDF document text
    • http://xn--b1afklwjc5g.xn--p1ai/ckfinder/userfiles/files/34056082253.pdfIn PDF document text
    • https://myupfield.link/wp-content/plugins/super-forms/uploads/php/files/m3mhde1nmu0evlqvh44r60q4ko/67736710955.pdfIn PDF document text
    • https://karinbentum.nl/uploads/file/boxavewepebaxa.pdfIn PDF document text
    • http://leadershipcareer.kr/fckeditor/_upload/file/59021740546.pdfIn PDF document text
    • https://ecomassage.pt/wp-content/plugins/super-forms/uploads/php/files/mlhl28cbsi03em0vgfnrfjg4pc/nivuboda.pdfIn PDF document text
    • https://aquaticlandscape.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606e84312c18f---vorezabamilure.pdfIn PDF document text
    • https://wlao.on.ca/wp-content/plugins/super-forms/uploads/php/files/4fba5793abeca9bdd831fd1f8fdfbd81/64733569422.pdfIn PDF document text
    • http://bigpictureresources.com/userfilesbigpicture/file/84333201394.pdfIn PDF document text
    • https://digbijoynath.in/iisc/ckfinder/uploads/userfiles/files/derovubavadudetomuviwus.pdfIn PDF document text
    • http://stevis.cz/files/file/58347924344.pdfIn PDF document text
    • http://www.netcorp.hu/data/editorfile/tosexusumowevanojogowidi.pdfIn PDF document text
    • http://liebherr-tr.com/userfiles/file/55795131309.pdfIn PDF document text
    • http://audiomaster.se/wp-content/plugins/formcraft/file-upload/server/content/files/161206525a09be---sasijinadusor.pdfIn PDF document text
    • http://krugernilssonreunion.org/clients/c/c3/c301050bdfa85653d7453904791897ac/File/dogavobonikosupevigape.pdfIn PDF document text
    • https://sfeerweter.nl/userfiles/files/dakagukoxasezakisanid.pdfIn PDF document text
    • http://bascobrunswick.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160a27b2cbd1a1---lokefajujigikaketimuk.pdfIn PDF document text
    • http://www.everhouse.lt/wp-content/plugins/formcraft/file-upload/server/content/files/160742fbee3fcd---95440641930.pdfIn PDF document text
    • http://springswellness.net/wp-content/plugins/formcraft/file-upload/server/content/files/1609bd21c3fb6e---40934903325.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_off0000d206.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD206 22000 bytes
SHA-256: 2445e15272357fc658f5f8d5ecadda2b19b063005e44a9d2ac43e7a50ab28461
font_01_sfnt_off00010a6a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A6A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012281.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12281 10976 bytes
SHA-256: fa5b01464ccbb5750f55b4d7375a95574f2fb94d9563a93118b7a6c6f3b5d85f

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