Malicious PDF — malware analysis report

Static analysis result for SHA-256 4a04c139ee0390a2…

MALICIOUS

PDF

75.1 KB Created: 2021-09-03 21:26:34 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 5fbeac998bc216ec3262d89838b639f4 SHA-1: 5359a3078f5de19d9ff019d06e1d5012929da02c SHA-256: 4a04c139ee0390a28b35890c25316340d651befef5fbf5b73cec725b7cee7832
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample contains embedded JavaScript, which is often used to exploit PDF vulnerabilities or redirect users to malicious sites. The presence of multiple external URIs, including links to compromised CMS uploads and disposable hosting, indicates a link farm designed to obscure the final destination and potentially distribute malware or phish for credentials. ClamAV detection and ML classification further support its malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9947

Heuristics 7

  • 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 farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://bephoangdung.vn/uploads/ckfinder/files/65213649914.pdf In PDF document text
    • https://firsatoyun.com/calisma2/files/uploads/nipifaronugido.pdfIn PDF document text
    • https://www.havanasalsa-dance-tours.com/wp-content/plugins/super-forms/uploads/php/files/c6d6f91a6c98d0362b269452a1816816/farenibofuv.pdfIn PDF document text
    • http://cbgnfinance.com/userfiles/file/21298037867.pdfIn PDF document text
    • http://hyosangjo.com/userfiles/file/20210626072702.pdfIn PDF document text
    • https://www.hinogas.com/wp-content/plugins/super-forms/uploads/php/files/sqaj24681jsig4d2q2u8hb377n/4341477140.pdfIn PDF document text
    • https://elicopter-de-inchiriat.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160a3bef110dc1---50415971098.pdfIn PDF document text
    • http://aybar-gallery.com/userfiles/files/26260205856.pdfIn PDF document text
    • https://nstoplana.rs/ckfinder/userfiles/files/juxegetosunat.pdfIn PDF document text
    • https://spitalmoldovanoua.ro/ckfinder/userfiles/files/40110313334.pdfIn PDF document text
    • https://deesudcoolingtower.com/userfiles/file/40705279178.pdfIn PDF document text
    • http://bensonlandscape.com/editorData/file/35917233471.pdfIn PDF document text
    • https://admonks.ru/wp-content/plugins/super-forms/uploads/php/files/c276a8e4fd49cdac285a01ac67d96f4d/72534913532.pdfIn PDF document text
    • http://tutek.eu/userfiles/file/xakuvowubu.pdfIn PDF document text
    • http://xn--b1ahhafccpgkb2bxo.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/c981cde6ddd5cbec1366caa92f012df5/fefopexakabaxukov.pdfIn PDF document text
    • https://barcelonacentromedico.es/files/galeria/files/4023553401.pdfIn PDF document text
    • https://pinotcar.com/wp-content/plugins/super-forms/uploads/php/files/b31bca3c839e31ab2aa640ca82b6206e/91651991754.pdfIn PDF document text
    • http://bergfin.se/wp-content/plugins/formcraft/file-upload/server/content/files/1609862f81cfee---51388807758.pdfIn PDF document text
    • http://osmed.cz/app/webroot/files/files/52351887545.pdfIn PDF document text
    • http://glcore.net/ckfinder/userfiles/files/pebovuwek.pdfIn PDF document text
    • https://tndvn.com/js/ckfinder/userfiles/files/gurizovire.pdfIn PDF document text
    • http://baugeraeteverleih.de/benutzerdateien/74839090356.pdfIn PDF document text
    • https://2greenchicks.com/wp-content/plugins/super-forms/uploads/php/files/742684f35d98c8beae6d389f2a3eab79/kodakopoguwula.pdfIn PDF document text
    • http://mfcwestenkwartier.nl/beta/userfiles/file/fokadapusabilobalopa.pdfIn PDF document text
    • https://micast.de/wp-content/plugins/super-forms/uploads/php/files/he9ui0v13su7fbmc0jdpbq38ch/73661647561.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=new+file+english+pre+intermediate+teacher%27s+book+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_off0000bdbc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBDBC 18200 bytes
SHA-256: 64591266823a73b9d60fe772ef9519cd8e65d170ef1c8b15b8e8e522ecdd3aa9
font_01_sfnt_off0000ec14.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC14 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001042b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1042B 11396 bytes
SHA-256: f1143331cc882405fe5f5cd4d3bbf8b35e43f971df592a86f7e2b2ac36816c38