Malicious PDF — malware analysis report

Static analysis result for SHA-256 43539ef5b826147a…

MALICIOUS

PDF

80.4 KB Created: 2021-09-07 06:21:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: f5cfc052ad89c0aabd71515f280efd72 SHA-1: d064963d6d75e73bc5589da7eb1ef9f78eb45967 SHA-256: 43539ef5b826147a1f219d17b69826339ee392629ec089ec392e76b79b68b35a
156 Risk Score

Malware Insights

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

This PDF was identified as malicious by a machine learning classifier and ClamAV, indicating it is likely a phishing or trojan delivery mechanism. The file functions as a link farm, containing numerous URLs that point to compromised WordPress upload directories and other disposable hosting sites, likely serving as a distribution point for further malicious payloads. The presence of multiple external URIs and the link farm structure strongly suggest an attempt to lure users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

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 http://kingsbrite.com/kingsbrite.com/userfiles/file/10022379233.pdf In PDF document text
    • http://www.webtony.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160b74229d3510---56688724322.pdfIn PDF document text
    • https://comesa.com.pe/wp-content/plugins/super-forms/uploads/php/files/14f5938a0447337d24c6b1914b24ab53/36219185485.pdfIn PDF document text
    • http://hicoweld.com/shop/fck_file/file/39669884706.pdfIn PDF document text
    • http://sh-ruiyangcpa.com/userfiles/file/2021-6///2021626543298104.pdfIn PDF document text
    • https://akdenizokullari.k12.tr/wp-content/plugins/super-forms/uploads/php/files/orcam4u4rgp80h417paidg0mbe/19843681845.pdfIn PDF document text
    • http://www.sevenchurchestour.net/seven/wp-content/plugins/formcraft/file-upload/server/content/files/1612742e89ba58---25542028392.pdfIn PDF document text
    • https://www.caesarstravel.com/wp-content/plugins/formcraft/file-upload/server/content/files/16084a06903032---jovew.pdfIn PDF document text
    • http://reclaimsplus.com/wp-content/plugins/super-forms/uploads/php/files/4d5b906155fde938da17000ad74fd9ca/tisuru.pdfIn PDF document text
    • https://www.infrascale.com/wp-content/plugins/super-forms/uploads/php/files/995a4d4686a97ad3fc51e19679f6f7a6/57536897096.pdfIn PDF document text
    • https://www.americansummercamps.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607785e910882---lavenok.pdfIn PDF document text
    • http://www.pirac.org/wp-content/plugins/super-forms/uploads/php/files/0c478786461c79412fc8cb8632906462/pabojenepowuveg.pdfIn PDF document text
    • https://designcoordinators.com/wp-content/plugins/formcraft/file-upload/server/content/files/16080bef38b7c5---42899684640.pdfIn PDF document text
    • http://www.reroofingbrisbaneqld.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1608f80562605f---misutu.pdfIn PDF document text
    • https://www.drserapkagan.com/wp-content/plugins/super-forms/uploads/php/files/unlnid1m45jkrd9570qdv78j46/nozolisopozugujop.pdfIn PDF document text
    • http://ingpoggi.eu/userfiles/files/17281057004.pdfIn PDF document text
    • http://driscollandgibson.com/images/edit_images/file/52876286868.pdfIn PDF document text
    • https://soalmatematik.com/userfiles/file/xamun.pdfIn PDF document text
    • http://0048.pl/48files/file/nujipezesixi.pdfIn PDF document text
    • http://hyunbulsa.org/~ewedd2/userfiles/file/xezelosimureperuzuwer.pdfIn PDF document text
    • https://leanuslab.com/UserFiles/file/dijobolasatolawojegufifox.pdfIn PDF document text
    • https://koncnc.com/genelresimler/file/sojojamir.pdfIn PDF document text
    • http://www.alfainstal.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160a6843c3a89b---tetotive.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1KS0DP0cxss/uplcv?utm_term=economics+definition+pdfPDF 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_off0000d852.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD852 17188 bytes
SHA-256: e8f9fad57204d992fd05f890312724ecab950e9c2ea59181e002b2f4e543af67
font_01_sfnt_off000104e4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x104E4 10456 bytes
SHA-256: b2cf18b741d5fd5ddfb5a45a0083386f0b3974c6821b5f8a853089ce3e149b9c
font_02_sfnt_off00011c95.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11C95 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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