Malicious PDF — malware analysis report

Static analysis result for SHA-256 87c38be44b167efc…

MALICIOUS

PDF

83.4 KB Created: 2021-09-20 03:11:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 9a41e359b98ba7a0f60e4c3757159b50 SHA-1: f2474a3c85bd09d43f03a7afea0ca6aa4edaa718 SHA-256: 87c38be44b167efc95ab702a4e6dfe7423a046ac08cdbdc1019b92e43d5a74d6
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised websites hosting further PDF files. This behavior is indicative of a link farm designed to redirect users to malicious content, likely for phishing or malware distribution. The ClamAV detection and ML classifier further support its malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 6

  • 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 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://mamnonsaokhue.vn/app/webroot/files/ckfinder/files/jukunipagolun.pdf
    • http://hopkim.vn/upload/files/14137806134.pdf
    • http://datacomsystems.cz/userfiles/file/giposi.pdf
    • http://extreamtuning.ru/wp-content/plugins/formcraft/file-upload/server/content/files/161434f2bbac05---mipek.pdf
    • http://prodesign31.ru/wp-content/plugins/formcraft/file-upload/server/content/files/161394cc0b6781---luzipu.pdf
    • https://icon-studios.com/userfiles/file/38168909746.pdf
    • https://floridainvestment.cz/files/file/64390142842.pdf
    • https://njsolarpower.com/wp-content/plugins/super-forms/uploads/php/files/c0e4ddc343193233aebe2d66bbd0c3a7/fevafunumirodisa.pdf
    • http://riccaassociati.eu/userfiles/files/wajatunidozozarenasem.pdf
    • https://callhfelectric.com/wp-content/plugins/formcraft/file-upload/server/content/files/16144173db0acc---tawiduvutunesaxozujagazi.pdf
    • http://crosswaysrecruitment.com/userfiles/file/sobezasisodom.pdf
    • https://xn--fct8ml6mwue.tw/uploads/files/fofebadimipuzapuja.pdf
    • http://pescepiana.eu/userfiles/files/60835394064.pdf
    • https://ashasuchikala.com/ckfinder/userfiles/files/gaxodesozi.pdf
    • http://kalmi.ru/upfiles/files/31285179125.pdf
    • https://www.keystonecare.co.uk/wp-content/plugins/super-forms/uploads/php/files/5cf73d1c9475a7d3a52d8ebbac7f5e30/95800341678.pdf
    • http://chieusangducphat.com/uploads/userfiles/file/46232322296.pdf
    • http://www.loockuniformes.com.br/home/wp-content/plugins/formcraft/file-upload/server/content/files/16146ebff13f74---ripipukonala.pdf
    • http://sns.hu/_user/file/nufupojut.pdf
    • http://plafondchauffant.fr/img/user/file/48236210960.pdf
    • http://chuanghuilaw.com/filespath/files/20210907205113.pdf
    • http://zjbfjt.com/upload/files/60212010746.pdf
    • https://advance-pack.com/editor_upload/file/rodarosotoxi.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=distinguish+between+prokaryotic+and+eukaryotic+cells+on+the+basis+of+nucleus
    • 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_off0000dd65.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xDD65 16792 bytes
font_01_sfnt_off0000f577.bin
345520e5bee488bdfafe8ec41545debcd1c8b63b917dbc90cb00edbc0af79a51
pdf-font-stream PDF embedded font (sfnt) at offset 0xF577 18112 bytes
font_02_sfnt_off0001248b.bin
2dc35717befedf84e5f04ef45b0c7c23729f483bc86248f39b119c5530ff1572
pdf-font-stream PDF embedded font (sfnt) at offset 0x1248B 11432 bytes