Malicious PDF — malware analysis report

Static analysis result for SHA-256 8b137f0e20c4b327…

MALICIOUS

PDF

71.8 KB Created: 2021-09-14 01:33:35 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 8bd97e0b17a76351423d1552a717ee69 SHA-1: d018a8f23aa334d7a6a9c6edfa504cafa815fab6 SHA-256: 8b137f0e20c4b327e59f91f09e743b29f1df5a2a41969445b5ff9e76b5713cbc
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as malicious by ClamAV and an ML classifier, with high-severity heuristics indicating PDF links to algorithmically generated URLs on potentially disposable domains. The presence of numerous external URIs, many with unknown reputations, strongly suggests a phishing or link-farming campaign. No scripts were extracted, but the overall structure points to a malicious PDF designed to redirect users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9840

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://eluvial.com/sites/all/sites/eluvial.com/files/22097164072.pdf In PDF document text
    • https://jooli.ru/ckfinder/userfiles/files/11583734347.pdfIn PDF document text
    • http://ohadalegistrocbarter.com/ckeditor/uploads/files/pisajajupuri.pdfIn PDF document text
    • http://intemhathanh.com/img_duhoc/files/kepumijesigovedozow.pdfIn PDF document text
    • http://presssimayeshahr.ir/pic/file/4396518266.pdfIn PDF document text
    • http://seoaudytor.pl/userfiles/file/lepavoxigulimipa.pdfIn PDF document text
    • http://cabanagarden.hu/editor_up/40996901438.pdfIn PDF document text
    • https://rm-parketi.si/uploads/lipoxagowonuvevem.pdfIn PDF document text
    • https://stthomasorthodoxchurchsouthpampady.com/userfiles/file/vowujijonalajuda.pdfIn PDF document text
    • http://conelser.hu/fck_uploads/file/giwigoxowar.pdfIn PDF document text
    • http://thietbimaugiao.vn/Images_upload/files/dogidewaxu.pdfIn PDF document text
    • http://biurod9.pl/public/userfiles/file/norelurifibexukuxakuwon.pdfIn PDF document text
    • http://podlahyadvere.sk/editor_uploads/system/files/walegedu.pdfIn PDF document text
    • http://assotechne.eu/userfiles/files/88426195818.pdfIn PDF document text
    • http://www.thebetterinsurance.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613a5b7776371---putosujeruziwegu.pdfIn PDF document text
    • http://ambulatorioveterinarioscapindandrea.it/userfiles/files/pimewo.pdfIn PDF document text
    • http://the-bom.kr/upfile/files/dozosazalusinoxi.pdfIn PDF document text
    • http://weldingplaza.com/files/file/85012628098.pdfIn PDF document text
    • https://mgc.to/sites/web/upload/files/81127160329.pdfIn PDF document text
    • http://eichler-kammerer.de/doweweg.pdfIn PDF document text
    • http://studioindelicato.com/userfiles/files/81950793849.pdfIn PDF document text
    • https://lakecountyoralsurgery.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613ad74b7a573---lerolipejorik.pdfIn PDF document text
    • https://tourpon.kr/FileData/ckfinder/files/20210911_EFE704FB9D8F3DDF.pdfIn PDF document text
    • http://l-max.ru/userfiles/file/3945158919.pdfIn PDF document text
    • https://horkolas-gatlas.hu/ufiles/file/satoxujofokibikazilisafax.pdfIn PDF document text
    • https://dazhonghua1688.com/ckfinder/userfiles/files/bamakomovebupunabifi.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/S30rS-6n6vg/uplcv?utm_term=organic+chemistry+demystified+pdfPDF 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_off0000b71e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB71E 16104 bytes
SHA-256: c2b83fc2f4e2fb8ef07937969c54f8887cc47c9e0fa3b3ce405c50be47d67ba8
font_01_sfnt_off0000dff7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDFF7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f80e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF80E 11040 bytes
SHA-256: c512951b608f675b77fa8e1a91f52aaff61c86c237d59ee872582cc54848cea0