Malicious PDF — malware analysis report

Static analysis result for SHA-256 81f62c28b1cb8328…

MALICIOUS

PDF

95.4 KB Created: 2021-09-17 16:47:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 81aa8420b2f10f369eb9f752ffbfb7fe SHA-1: 0a6090c63ea6ba87dad1231be42bc7f9551ed2e3 SHA-256: 81f62c28b1cb8328bf7b385ae79f9f0b805fd2d7e01be8548912777504e74fef
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was identified as malicious by ML classifiers and ClamAV, specifically flagged as a phishing trojan. It contains numerous external links, many pointing to compromised CMS upload storage or disposable hosting, suggesting a link farm designed to redirect users to malicious sites. While no scripts were explicitly extracted, the PDF structure and link farm heuristic indicate an attempt to leverage external resources for malicious purposes, likely spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9820

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://pharmabiosolutions.com/filespath/files/20210909132409.pdf In PDF document text
    • https://nolimitscenter.be/peausitive/images/FCKeditor/file/rijadur.pdfIn PDF document text
    • http://lagrupacio.cat/file/7388481558.pdfIn PDF document text
    • https://icon-studios.com/userfiles/file/fifelinidexubogut.pdfIn PDF document text
    • https://glass-haus.ru/wp-content/plugins/super-forms/uploads/php/files/2670c92aa91195890563fd2202c0ab0d/mejezejisimaresovemariv.pdfIn PDF document text
    • https://gencshoworganizasyon.com/upload/ckfinder/files/kelenoxavis.pdfIn PDF document text
    • http://bjdfszwy.com/filespath/files/20210910093849.pdfIn PDF document text
    • http://www.de.ruben.pl/ckfinder/userfiles/files/lilosudek.pdfIn PDF document text
    • http://www.norestim.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16135c254a7c61---zekaxukutufupisanukub.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/16140c0c682d36---99401790399.pdfIn PDF document text
    • https://currenwatch.myhost360.cn/file/upload/files/09-16-14-59-26-45.pdfIn PDF document text
    • https://www.gico.ge/ckfinder/userfiles/files/forurof.pdfIn PDF document text
    • http://world-green-hope.com/uploads/files/12022906363.pdfIn PDF document text
    • https://mjrspot.com/fckimages/file/36663980492.pdfIn PDF document text
    • https://promenade-perpignan.com/userfiles/file/bisunufonuxizezoxa.pdfIn PDF document text
    • https://fwstc.in/userfiles/file/71637521693.pdfIn PDF document text
    • http://olgapolyakova.de/files/files/7737293588.pdfIn PDF document text
    • http://ontheedgeofnow.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139a19bb2d7a---zuwuxojexatijolexo.pdfIn PDF document text
    • https://sahodayabbsr.com/test/fckeditor/file/zojenani.pdfIn PDF document text
    • http://aytekinpolatel.com/image/files/79302533069.pdfIn PDF document text
    • http://xn--365-pn7mwb654m2qn.com/ckupload/files/37081616454.pdfIn PDF document text
    • https://sahodayabbsr.com/test/fckeditor/file/jadere.pdfIn PDF document text
    • http://www.s4b.nl/upload/files/78395920106.pdfIn PDF document text
    • http://airelimpio.mx/img/editor/file/wafejevusaretabilivubom.pdfIn PDF document text
    • http://forter.vn/hinhanh/file/75033394291.pdfIn PDF document text
    • http://honeycontacts.com/uploades/userfiles/file/62117698692.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/FevRqgeaUVY/uplcv?utm_term=get+free+trial+followers+on+instagramPDF 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_off00010f54.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10F54 18416 bytes
SHA-256: 63ccd4b6916538b6e552230796622a434545a25aba453a59ea7b3e7339666379
font_01_sfnt_off00013f50.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13F50 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00015767.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15767 10684 bytes
SHA-256: 23e4abc8d436fb0000d45b30bc7cb310f136f7fb179145ea9e534eb22933b008

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