Malicious PDF — malware analysis report

Static analysis result for SHA-256 21f1ddd608e11e57…

MALICIOUS

PDF

88.0 KB Created: 2021-08-02 08:56:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 0b6d47478d8168afd6eeab92bc782aa0 SHA-1: 88d24b04b84d3f931cd70796fdc49524c434c474 SHA-256: 21f1ddd608e11e57fa2201f189cf8e1d8b10a18d2c212eaf337bfc7b4487f26c
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file was flagged by multiple heuristics and a machine learning classifier as malicious, with ClamAV identifying it as a phishing trojan. It contains numerous embedded URLs, many pointing to compromised WordPress sites or disposable hosting, suggesting a link farm designed to redirect users to malicious content. The presence of these links and the nature of the heuristics indicate an attempt to exploit users through deceptive redirection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9986

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://medvor.ru/uplcv?utm_term=arihant+mht+cet+previous+year+question+papers
    • http://munnarinfo.in/userfiles/file/46920419223.pdf
    • http://sun-green.be/ckfinder/userfiles/files/zotutalodulanezifatonikif.pdf
    • http://cautrucpalang.vn/webroot/img/files/61466889832.pdf
    • https://www.sahabatkeluargahomecare.com/wp-content/plugins/formcraft/file-upload/server/content/files/160deac4e8b668---91933709598.pdf
    • http://hoanggiaphatland.com/uploads/image/files/16135972308.pdf
    • http://www.oknookna.pl/wp-content/plugins/formcraft/file-upload/server/content/files/16094c68462bad---fitisovubowon.pdf
    • http://smepil.com/ckeditor/userfiles/files/xerexok.pdf
    • https://brunoamaranti.it/wp-content/plugins/super-forms/uploads/php/files/6kvlo02tbb1qasm2p0s0alf4r6/22870006669.pdf
    • http://geo-equipe.it/userfiles/files/ximonepagabufogitesoven.pdf
    • https://www.lipfish.no/wp-content/plugins/formcraft/file-upload/server/content/files/1607951502fcf3---29091012870.pdf
    • http://worldofpacifiers.com/editor_uploads/system/files/viluvumakiladumulapijo.pdf
    • http://dohertylaw.net/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/musejugizibibokimegukokug.pdf
    • http://immodraft.nrw/images/architekten_agentur_images_/file/legadivona.pdf
    • http://saydersan.com/firma/files/10387344844.pdf
    • https://clubforeducation.com/FCKeditor/userfiles/file/40560898576.pdf
    • https://castilloexterior.net/ckfinder/userfiles/files/83881024608.pdf
    • http://kanalprofi.at/UserFiles/file/vumagifuxo.pdf
    • http://anhuishangbiao.com/upload_fck/file/2021-4-30/20210430111619961386.pdf
    • https://goactive.hu/wp-content/plugins/super-forms/uploads/php/files/9eda72fc8acda9499d8a59d467dc3a3b/poxilajumigol.pdf
    • https://www.darrellstuckey.com/wp-content/plugins/formcraft/file-upload/server/content/files/16088438bba99d---87663587138.pdf
    • http://www.ctnphrae.com/ckfinder/userfiles/files/4775038268.pdf
    • http://staractivecollection.com/resimler/site/files/dejinuxefa.pdf
    • https://kingyao.com/uploadfiles/files/20210614_100542_3980.pdf
    • http://www.christinemartin.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160a77971c3425---mokavaduk.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f31a.bin
8eaf1dac5d6a862a8fe8808a18d86b4ccdbbc661b73b09b5667ab5d4a9bfbe63
pdf-font-stream PDF embedded font (sfnt) at offset 0xF31A 11000 bytes
font_01_sfnt_off00010c8c.bin
a99f54940b7786c0fc3aa14798904c344a9bcf2ee7826bf94955bfbd4c130a93
pdf-font-stream PDF embedded font (sfnt) at offset 0x10C8C 17108 bytes
font_02_sfnt_off00013927.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x13927 16792 bytes