Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4369d95161a3d6a…

MALICIOUS

PDF

69.2 KB Created: 2021-09-28 05:19:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 1668d4b9929d1c53e5d34fc697fdc233 SHA-1: 9631d3b6b3b413c3784ab8c26d722fa0053b6688 SHA-256: b4369d95161a3d6adc9e387ba3c6f140cbca066da9331ef1ff7fc5f9a7f90c71
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF was flagged by ClamAV as Pdf.Phishing.Trojan and by an ML classifier as malicious. It contains numerous external links to other PDF files hosted on disposable domains, indicating it functions as a link farm. The heuristic PDF_SEO_DISPOSABLE_LINK_FARM specifically identifies this pattern of hosting many small PDFs on disposable domains. The presence of external URIs and the overall structure suggest a phishing or malware distribution attempt, likely delivered via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

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 https://smidgel.ru/uplcv?utm_term=discard+credit+card+number+generator PDF link annotation
    • http://nemdanangpho.com/uploads/2021-09-27/images/files/30107112928.pdfIn PDF document text
    • http://www.luna1956.com/images/library/File/zigexeda.pdfIn PDF document text
    • http://ambulatorioveterinariosantanna.eu/userfiles/files/dadezimamijuj.pdfIn PDF document text
    • http://bluebiz.kr/userData/board/file/83428886826.pdfIn PDF document text
    • http://www.hcibatiment.fr/wp-content/plugins/formcraft/file-upload/server/content/files/161400553f24de---valuvotiwaxutebutez.pdfIn PDF document text
    • http://ydtmuhendislik.com/ckfinder/userfiles/files/fewanoruvabonojix.pdfIn PDF document text
    • https://mercedesmazo.es/wp-content/plugins/formcraft/file-upload/server/content/files/1614becf6434d5---17824653834.pdfIn PDF document text
    • http://chapelguild.com/images/usr/48967745811.pdfIn PDF document text
    • http://praguetransfer.com/files/file/24732999038.pdfIn PDF document text
    • https://www.gullyracing.it/admin/ckfinder/userfiles/files/47020407332.pdfIn PDF document text
    • http://www.coverseg.com/uploads/ckfinder/files/gudusonazeg.pdfIn PDF document text
    • http://biaikatolikus.hu/files/file/nepuvebizegelegiw.pdfIn PDF document text
    • http://herve-coiffure.ci/files/48943097861.pdfIn PDF document text
    • https://queensflower.nl/clientfiles/wupegomunemanezugojaf.pdfIn PDF document text
    • http://kht.civilkozpont.hu/uploads/file/91134740315.pdfIn PDF document text
    • http://baodieptailor.com/uploads/2021-09-20/images/files/xadox.pdfIn PDF document text
    • http://gachtrangtritranvinhtin.com/gachtrangtritranvinhtin/Images_upload/files/simugeburuzu.pdfIn PDF document text
    • http://turinhotelcompany.com/userfiles/files/laxelunewi.pdfIn PDF document text
    • https://hssanesteban.cl/files/55274965721.pdfIn PDF document text
    • http://xn--80aer5aza.xn--c1acndkmcarx.xn--p1ai/ckfinder/userfiles/files/renoke.pdfIn PDF document text
    • http://suarezbeltran.com/aym_images/files/revedewibov.pdfIn PDF document text
    • https://eyetracking.pl/userfiles/file/zifebularewafulawotomet.pdfIn PDF document text
    • http://tobn56.com/UpFiles/file/48384017464.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_off0000b067.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB067 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000c87e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC87E 10908 bytes
SHA-256: 330a4879a74ae64c506802a9b7d41f0268e975e876c41d53d6ffdf0c533125d8
font_02_sfnt_off0000e18b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE18B 14972 bytes
SHA-256: 0696485f14b8c7a2839cd49128ef0e453be9a03d64ae55779e9fa33319a0fd7d