Malicious PDF — malware analysis report

Static analysis result for SHA-256 83e56639bf8c8047…

MALICIOUS

PDF

85.0 KB Created: 2021-09-18 12:42:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 52bf12749a576b4a33afdd15ef198076 SHA-1: c15290bf5e0de89d4a341fedd14ab3c2574a8b1a SHA-256: 83e56639bf8c8047e9c134f306a2d33853430dd7f9e416512f42fbb6ab30f8cf
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links to external resources, many of which are hosted on disposable domains and appear to be part of a link farm. The ML classifier and ClamAV detection strongly indicate malicious intent, likely to trick users into downloading further payloads. The presence of PDF_RANDOM_URL_LINK and PDF_SEO_DISPOSABLE_LINK_FARM heuristics confirms the nature of the attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9952

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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://autoscuolemontagna.it/userfiles/files/nikubafadonafebaxer.pdf In PDF document text
    • http://carraracucinecomponibilitrapani.it/userfiles/files/bazajofobuzegemizeged.pdfIn PDF document text
    • https://gmt-tw.com/app/webroot/userfiles/files/fupedorafenotelumavu.pdfIn PDF document text
    • http://unionasset.net/file_upload/spaw_upload/file/20210903201503.pdfIn PDF document text
    • http://chothuexeninhbinh.net/data/dulieu/files/91373359951.pdfIn PDF document text
    • http://merklink.nl/site/data/ws/files/papiwebagidumadodimefovis.pdfIn PDF document text
    • https://jiu-hang.com/upfiles/editor/files/tujoniwabijisixelutig.pdfIn PDF document text
    • http://atthaya.com/file_media/file_image/file/tujujifa.pdfIn PDF document text
    • http://ros-grad.ru/fck_editor_files/files/suvipaxedovis.pdfIn PDF document text
    • http://tradotel-riviera.com/file/59515683224.pdfIn PDF document text
    • https://manorhair.com/uploads/files/202109051403184593.pdfIn PDF document text
    • http://clubselectionvoyages.net/images/file/34034542821.pdfIn PDF document text
    • http://mywymc.com/userfiles/file/94997860726.pdfIn PDF document text
    • https://hsse.hssanesteban.cl/files/marepurugejixumikunoza.pdfIn PDF document text
    • https://maximatrimony.com/ckfinder/userfiles/files/zixumumutux.pdfIn PDF document text
    • https://hattoco.vn/images/ckeditor/files/bowigidovupu.pdfIn PDF document text
    • https://purmoradiatoriai.lt/images/files/zenarexara.pdfIn PDF document text
    • https://mwasafat.com/uploads/files/getewapajap.pdfIn PDF document text
    • http://funagamex.vn/PhuongNamGroup/userfiles/files/70110863375.pdfIn PDF document text
    • http://kpotplace.com/uploads/files/18214093122.pdfIn PDF document text
    • http://fcv-bo.org/data/fcv-bo/userfiles/file/dilinofoxilumajozarorisop.pdfIn PDF document text
    • http://www.patricktennis.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1613b9fa8084a4---36772288277.pdfIn PDF document text
    • http://touchpanelpro.com/upload/files/36819184634.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/fzgW7-mxBc0/uplcv?utm_term=vidmate+android+phonePDF 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_off0000e55a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE55A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fd6c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD6C 19340 bytes
SHA-256: d5173e70caa36b2f82ff4bfa7155699696b88008346e2b54c6c8b9d5c62833d1
font_02_sfnt_off00012fb4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12FB4 10412 bytes
SHA-256: ece05f9150475b558a4d624a4256f16b3d3a71f8da252b44147b2639de75da13