Malicious PDF — malware analysis report

Static analysis result for SHA-256 a82b5bce714ff1ac…

MALICIOUS

PDF

71.6 KB Created: 2021-09-29 03:12:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 813f083dfd0d97fbf1102b4c2e3d8884 SHA-1: 76e373062fa4221f435cf1360569a144e09bb23a SHA-256: a82b5bce714ff1ac5a23c85f191080a1739dcc925e393d774bfb758a08bed5de
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains embedded JavaScript, which is often used to exploit PDF vulnerabilities or redirect users. The presence of numerous external URIs, including links to compromised CMS uploads and disposable hosting, suggests a link farm designed to obscure the ultimate destination, likely a phishing page or malware download server. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, indicating a tactic to distribute malicious content through a network of seemingly unrelated sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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=bixby+voice+activation PDF link annotation
    • http://powerfalcon.net/uppic/files/74992324717.pdfIn PDF document text
    • http://yogathoitrang.com/quangbasanpham/app/webroot/upload/image/files/78525564852.pdfIn PDF document text
    • https://girisimhaber.com/uploads/file/wimep.pdfIn PDF document text
    • http://becro-plast.hr/wp-content/plugins/formcraft/file-upload/server/content/files/1613dcd7c114c9---pipijazanexebofobumozawom.pdfIn PDF document text
    • https://precisionautoandac.com/wp-content/plugins/super-forms/uploads/php/files/f98a94677771445b1e4742cd61af0932/zetavoxulujurogek.pdfIn PDF document text
    • http://cps-mbstu.edu.bd/app/webroot/js/ckfinder/userfiles/files/nijuvusosed.pdfIn PDF document text
    • http://www.uc-kushiro.net/images/library/File/80879204428.pdfIn PDF document text
    • http://lakesnwoodskerala.com/uploads/file/94761190602.pdfIn PDF document text
    • https://2winit.com/Files/files/92739583912.pdfIn PDF document text
    • http://oxigensupplies.com/shipinc/userfiles/files/bokufiligimof.pdfIn PDF document text
    • http://dietaltop.com/userfiles/files/4592018444.pdfIn PDF document text
    • http://hengtongrongshang.com/jingkelun/userfiles/files/20210927215727.pdfIn PDF document text
    • https://nvsrolko.org/ckfinder/userfiles/files/77707842215.pdfIn PDF document text
    • https://www.bmo-agencement.fr/ckfinder/userfiles/files/manujanuxeluwutovakiz.pdfIn PDF document text
    • https://maryamghiasi.com/images/upload/files/somovuxunolasabolep.pdfIn PDF document text
    • http://alwaditrading.com/userfiles/files/89708439051.pdfIn PDF document text
    • https://epiphanych.com/images/file/xiruxovegewiravuvexa.pdfIn PDF document text
    • http://randygordonlawoffice.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/rivikezosezagifoburipi.pdfIn PDF document text
    • https://ohcsi.com/ckfinder/userfiles/files/laboromonapizugu.pdfIn PDF document text
    • http://aimecostruzioni.it/userfiles/files/19572080003.pdfIn PDF document text
    • http://cz-synergy.cz/data/file/31546087710.pdfIn PDF document text
    • https://www.northamericatalk.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e5e60b646a---76012891996.pdfIn PDF document text
    • https://istanajp.com/contents/files/nugokudegagifilumuwodibi.pdfIn PDF document text
    • http://raduzhniy.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613db780deb3b---fabibebejobukopamar.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_off0000b503.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB503 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cd15.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCD15 17160 bytes
SHA-256: a94b12417022b7ac73114ee80fa6ddce6447af0b577fcdffee91f4b5968f2ca9
font_02_sfnt_off0000f945.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF945 10384 bytes
SHA-256: 0cd3115a2c97561ada654f1b162d3148dd090ceb431e4fddfa31cabc4c023860

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