Malicious PDF — malware analysis report

Static analysis result for SHA-256 dfa593ec4f903af4…

MALICIOUS

PDF

69.5 KB Created: 2021-10-03 14:58:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 01866899fc158489fc71420d59c40ea1 SHA-1: 4eacd50f0de0e33601cebd05ea2b4f23ecf0a331 SHA-256: dfa593ec4f903af482b6fad8658c213534f0bb2d11b733e20f56b1e94a63e7ed
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, containing numerous external URLs pointing to other PDF files hosted on various domains. The PDF_RANDOM_URL_LINK heuristic specifically highlights a link to an algorithmically generated URL, suggesting an attempt to obscure the malicious destination.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9950

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 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://yanartekstil.com/firma/files/99933313898.pdf In PDF document text
    • http://fabtur.ru/upload/files/92664974623.pdfIn PDF document text
    • http://ondrejkocar.cz/img/file/kunugodugug.pdfIn PDF document text
    • http://shinhwajudan.com/userData/board/file/fofatiwowaji.pdfIn PDF document text
    • http://matsusushionline.com/uploads/files/vineko.pdfIn PDF document text
    • http://ambulatorioveterinarioilghirlandaio.it/userfiles/files/muvexetemozivamugazevat.pdfIn PDF document text
    • https://posaonakosovu.com/ckfinder/userfiles/files/45446376170.pdfIn PDF document text
    • http://www.aportecnica.com/imagenes/editor/file/68891090744.pdfIn PDF document text
    • http://xn--90aoa5aj.xn--p1ai/ckfinder/userfiles/files/vazaretinenizafajewini.pdfIn PDF document text
    • http://nayyaralidada.com/alpha/ckfinder/userfiles/files/mutavagal.pdfIn PDF document text
    • http://bookblog.kr/data/file/files/bapubuzokukogidojax.pdfIn PDF document text
    • http://interroadholland.nl/userfiles/file/peberagewos.pdfIn PDF document text
    • http://ddservice-bmw.pl/userfiles/file/sikezukubamaletuxareji.pdfIn PDF document text
    • https://myphambambi.com/webroot/img/files/teruvu.pdfIn PDF document text
    • https://italvaping.com/file/kulamalejo.pdfIn PDF document text
    • https://www.reparaciondebomba.com.ar/wp-content/plugins/super-forms/uploads/php/files/4n8jlm24k1912bko666qfjgrm7/45608218813.pdfIn PDF document text
    • https://west-holding.com/userfiles/file/bupupo.pdfIn PDF document text
    • http://casaatlantida.com/userfiles/file///siwinixogowuta.pdfIn PDF document text
    • https://gdwtechnology.com/fckeditor/file/In PDF document text
    • http://studio-castiglioni.com/userfiles/files/zusisagusubezak.pdfIn PDF document text
    • http://xn----9sbbnbtte4cyg.xn--p1ai/ckfinder/userfiles/files/10823637821.pdfIn PDF document text
    • http://gwtcs.org/Content/uploads/files/46584805141.pdfIn PDF document text
    • http://vatlieubaooncachnhiet.com/userfiles/file/3903498414.pdfIn PDF document text
    • http://rapet.hu/files/rivuvomebotixakox.pdfIn PDF document text
    • http://hasanmasat.com/ckfinder/userfiles/files/28385512472.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1xuhb7AK25c/uplcv?utm_term=middleware+object+is+not+callablePDF 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_off0000af80.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAF80 15180 bytes
SHA-256: 306dd4f2a7d52bae99c8d03c9471579896b8a2e972cf0e6f0d48776462b01954
font_01_sfnt_off0000d5e4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD5E4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000edfb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEDFB 10712 bytes
SHA-256: 90ea427c72f331a9acfbc0870f610dd6ecaca4f48b025eec856ef3f818b7f090