Malicious PDF — malware analysis report

Static analysis result for SHA-256 caff5c6882d366ba…

MALICIOUS

PDF

79.5 KB Created: 2021-09-18 16:00:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-21
MD5: 3a7ac3fa8d6d957a463c07cae312a462 SHA-1: b1371850d4112121f7bf870786f16f6e628d3427 SHA-256: caff5c6882d366baa619a6b63ef52cef23afb6d0795d9db6c9fdc4fa097f442e
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many pointing to disposable domains, suggesting a link farm designed to redirect users to malicious content. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, indicating a large number of links on disposable hosting. No scripts were extracted, but the overall structure and URL distribution strongly suggest a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://laborke.ru/uplcv?utm_term=kruti+dev+excel+to+pdf PDF link annotation
    • https://sandipkumardutta.com/ckfinder/userfiles/files/87487868862.pdfIn PDF document text
    • http://fuhua.tumujike.com/assets/upload/files/202109080125239820.pdfIn PDF document text
    • http://tuvantindat.com/uploads/2021-09-17/images/files/vajemav.pdfIn PDF document text
    • http://lamorenj.com/userfiles/files/58510637469.pdfIn PDF document text
    • http://jikaramen.com/uploads/files/71663811395.pdfIn PDF document text
    • http://bsinteriordesigner.com/userfiles/files/bitadebukaxizokinewepe.pdfIn PDF document text
    • http://j1medical.com/uploaded/file/xibowanofoxada.pdfIn PDF document text
    • https://orkhaconstruction.com/wp-content/plugins/super-forms/uploads/php/files/kiithto2sgj1gh03g82f586iv8/ribunepefogekek.pdfIn PDF document text
    • http://weilandensemble.nl/ckfinder/userfiles/files/giwewesasokobamitixasute.pdfIn PDF document text
    • http://escuelasfutbol8.com/docs/files/45782187223.pdfIn PDF document text
    • http://cualuoiskydoor.com/webroot/img/files/gigowagovetibozafubotula.pdfIn PDF document text
    • http://3t-t.com/User_File/UpFile/file/20210907092451_YnVtZWx1cHVtaWxlZmVsaXN1eA==.pdfIn PDF document text
    • http://willajarmar.pl/userfiles/file/jinubimexasidilufasukife.pdfIn PDF document text
    • http://uitvaartverzorgingsindex.nl/images/uploads/lasamowudaraxojojeliladu.pdfIn PDF document text
    • http://bienchidan.org/uploads/files/kezusumufevekuk.pdfIn PDF document text
    • http://peak-experience-japan.com/images/blog/file/gitatulemelilala.pdfIn PDF document text
    • https://lensmam.com/userfiles/file/gakopogumeberap.pdfIn PDF document text
    • http://japanbizkorea.com/userData/ebizro_board/file/67059090206.pdfIn PDF document text
    • http://lukinserv.hu/file/gadaloz.pdfIn PDF document text
    • http://runwellconsulting.eu/file/file/32876063888.pdfIn PDF document text
    • http://ghettaetamionarchitetti.it/userfiles/files/zuxiven.pdfIn PDF document text
    • https://gullyracing.it/admin/ckfinder/userfiles/files/23825658968.pdfIn PDF document text
    • https://jurad.eu/files/file/posor.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_off0000d21e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD21E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ea35.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA35 10440 bytes
SHA-256: 1ba98024e65ad18b26d02bedafdf0e173b8421d271a7e8e912f5b1f7fda8637b
font_02_sfnt_off00010200.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10200 17928 bytes
SHA-256: 93c11ff04aeab500164602567de34b5c8fb355da7a2ee966cef990c661a63bb5