Malicious PDF — malware analysis report

Static analysis result for SHA-256 37f849943dee8b45…

MALICIOUS

PDF

79.4 KB Created: 2021-09-13 13:48:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: b66cfe76af32bb3d91fade4834c91b8f SHA-1: e41608cec9381ef895479992cba08dc79599bdab SHA-256: 37f849943dee8b4530df3fd88e8e653dff2468b78e00e98ab8f3dd93faee9f81
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains multiple links to external websites, with several heuristics indicating these are part of a link farm on compromised or disposable hosting. The ClamAV detection and ML classifier strongly suggest malicious intent, likely phishing or malware delivery. No scripts were extracted, but the presence of numerous external links points to an attack pattern involving directing users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

Heuristics 7

  • 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.
  • 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://tieuhocsongphuong.hoaiduc.edu.vn/ckfinder/userfiles/files/jovowewalikaguxixa.pdf In PDF document text
    • https://hankilfood.com/upfile/files/10767407348.pdfIn PDF document text
    • https://internationallanguagenavigators.com/media/vejamogifofogajanapif.pdfIn PDF document text
    • https://trichynext.com/wp-content/plugins/super-forms/uploads/php/files/eb7fd6c5bf9ec46ccbc26b5df92c212e/30918076802.pdfIn PDF document text
    • https://novahealthclinic.ca/userfiles/file/giwapesemezuvewoguw.pdfIn PDF document text
    • http://www.gcsystem.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1612fafc8446c5---72841679001.pdfIn PDF document text
    • https://sahodayabbsr.com/test/fckeditor/file/68714736965.pdfIn PDF document text
    • https://o-dance.com/upload/files/ravasikapupubezerile.pdfIn PDF document text
    • http://www.farmaciabergua.com/userfiles/files/83192139486.pdfIn PDF document text
    • https://cr2tek.com/userfiles/Proj_Name/files/fudodejafolejaberip.pdfIn PDF document text
    • http://trenermichal.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1613ef61abb1ad---bevewozigivimosi.pdfIn PDF document text
    • http://articolo17.it/siti/usr/foto/files/jujakakupukegedaned.pdfIn PDF document text
    • http://toyotaquangninh.org/data/dulieu/files/69093233051.pdfIn PDF document text
    • http://inspirationallabels.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1613c3a9c441da---pejinurelimarazeme.pdfIn PDF document text
    • http://hoteldanang.com/uploads/images/files/koriritenogupilazo.pdfIn PDF document text
    • http://ballarioarchitetti.eu/userfiles/files/gutobarupadez.pdfIn PDF document text
    • https://www.confirmedtour.com/files/zitexawepilivetuk.pdfIn PDF document text
    • http://konberdbio.com/upload/files/2050879756.pdfIn PDF document text
    • http://toanthinh.vn/webroot/img/files/1999394300.pdfIn PDF document text
    • http://we2meeting.com/ckfinder/userfiles/publics/files/98211015091.pdfIn PDF document text
    • http://www.jhannahs.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613cf7bff3c30---tirezanivomese.pdfIn PDF document text
    • http://stroynerud-sm.ru/wp-content/plugins/formcraft/file-upload/server/content/files/161302638e8c72---62490642479.pdfIn PDF document text
    • http://megat.pl/uploaded/fck_files/file/31907622912.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/GLLx1DTH0VQ/uplcv?utm_term=best+adblock+extension+chromePDF 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_off0000d07c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD07C 17648 bytes
SHA-256: 8dbc11b5fed7a6a566013cc2cf7f7dac5fb7480c0ac466cc2d67ae1c7140b7ac
font_01_sfnt_off0000fe4d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE4D 11020 bytes
SHA-256: 5e38bc25c6189c8fdf1e7075f1a91d97ffa6a74fe66db5c56ad891640a23ff69
font_02_sfnt_off000117c5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x117C5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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