Malicious PDF — malware analysis report

Static analysis result for SHA-256 728766cd2b5d7cf8…

MALICIOUS

PDF

73.4 KB Created: 2021-10-04 01:08:00 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: b65bea70777bb3a32a376c45f264a250 SHA-1: fcd56a0524781f4dd0b62320af3d8cd6dcd3a786 SHA-256: 728766cd2b5d7cf819e9154e67b8f6732922b3f4e60e6b4ab69b6ffd65b7441d
156 Risk Score

Malware Insights

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

The PDF contains numerous links, many hosted on compromised or disposable domains, indicating a link farm designed to redirect users to malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware distribution. No scripts were extracted, so the primary attack vector appears to be the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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://terezszilvia.com/images/uploaded/file/32835063380.pdf In PDF document text
    • https://pensiuneavalentina.ro/app/webroot/file/difesukis.pdfIn PDF document text
    • https://aneri12.eu/res/file/94561906789.pdfIn PDF document text
    • https://xn--espaoldetalca-lkb.cl/var/www/html/upload/file/budasan.pdfIn PDF document text
    • https://inchiriereelicoptere.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1613b97feb67cc---kivobagijiledugut.pdfIn PDF document text
    • https://stratasphere.online/userfiles/file/35605759074.pdfIn PDF document text
    • http://ombs.ru/uploads/files/jorajuvipivelaw.pdfIn PDF document text
    • http://modelkyujin.com/wp-content/plugins/formcraft/file-upload/server/content/files/16151a6292ecc7---31972317117.pdfIn PDF document text
    • https://frenstravel.com/assets/ckfinder/userfiles/files/17290891073.pdfIn PDF document text
    • http://wadsoda.com/UserFiles/File/vozolep.pdfIn PDF document text
    • http://kanchanaspa.com/ckfinder/userfiles/files/xobonevizozukojave.pdfIn PDF document text
    • http://ladyvenus.it/userfiles/files/xirezo.pdfIn PDF document text
    • http://186086.com/upload/files/tuzotij.pdfIn PDF document text
    • https://klingende-zeder.de/wp-content/plugins/formcraft/file-upload/server/content/files/1615412e3b6005---fakujagumivepeziduvejabu.pdfIn PDF document text
    • http://personal.sut.ac.th/chantira/port/ckfinder/userfiles/files/dujavifetubilugido.pdfIn PDF document text
    • https://ensegun2.com/ckfinder/userfiles/files/47227955268.pdfIn PDF document text
    • http://taxiluzern.ch/khurasan/userfiles/files/deribedeg.pdfIn PDF document text
    • https://szpital-sulecin.pl/images/fckfiles/file/83264359353.pdfIn PDF document text
    • https://dedywiredja.com/wp-content/plugins/formcraft/file-upload/server/content/files/161431609eb3e7---muwagubesofudalobusu.pdfIn PDF document text
    • http://geologicatoscana.eu/userfiles/files/jisokomokaziririvixumo.pdfIn PDF document text
    • https://prestinireedcorp.com/userfiles/files/mawuxopozipolanarufikolem.pdfIn PDF document text
    • http://burragebrothers.net/demo/jolie/beta/userfiles/files/xeripoxasolame.pdfIn PDF document text
    • https://kemxoithanhhang.vn/app/webroot/files/images/pages/files/fororulenegugu.pdfIn PDF document text
    • http://ansatrans.ru/admin/ckfinder/userfiles/files/31724178325.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/3CAf4wW3hvY/uplcv?utm_term=oxidation+no+of+cr+in+k2cr2o7PDF 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_off0000b6b4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB6B4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cecb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCECB 10512 bytes
SHA-256: 8ff1c2900f4191909d270b13d91ca5d9a61ecedd4fa9dfc60f2feb2bdfbcdcb8
font_02_sfnt_off0000e6f8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE6F8 19156 bytes
SHA-256: 532338c0c8d3a6f0e7c91d150ae439597563893d2b8a29e307ab8d9c6d3f69c5