Malicious PDF — malware analysis report

Static analysis result for SHA-256 fd437a6a6780731a…

MALICIOUS

PDF

71.8 KB Created: 2021-09-28 16:36:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 638bed11cce5180ed45afec2cb382d3b SHA-1: f0c159dc018d5006c955b6289900717bb2b56045 SHA-256: fd437a6a6780731aa8b25d05677f5d5cfcc9ed7f76d73e4db292a027ecdf528b
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous external links, many of which point to other PDF files hosted on disposable domains, indicating a link farm designed to distribute malicious content. The ClamAV detection and ML classifier strongly suggest malicious intent, likely phishing or malware delivery. Although no scripts were explicitly extracted, the PDF structure and URL patterns are consistent with malicious PDF lures.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

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 https://huntic.ru/uplcv?utm_term=ibis+paint+x+apk+android PDF link annotation
    • http://navigator-nsk.ru/userfiles/file/budewin.pdfIn PDF document text
    • http://akvatoria.by/UserFiles/files/30687091270.pdfIn PDF document text
    • http://bezpiecznamlodosc.org/files/file/69434181448.pdfIn PDF document text
    • http://erfaspot.com/resimler/files/91184777933.pdfIn PDF document text
    • http://yas-center.ru/userfiles/file/9332873490.pdfIn PDF document text
    • http://xn--o39a91gvwm83kbsn.com/FileData/ckfinder/files/20210917_196252B48E1F8278.pdfIn PDF document text
    • http://ambulatorioveterinarioscapindandrea.it/userfiles/files/43942494515.pdfIn PDF document text
    • http://www.kinoimaging.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1612f49d1497d9---8114186748.pdfIn PDF document text
    • https://rent-1.es/ckfinder/userfiles/files/45008466714.pdfIn PDF document text
    • https://cremyco.com/app/webroot/docs/file/dusegele.pdfIn PDF document text
    • https://www.delaneyllc.com/ckfinder/userfiles/files/dotolarekegevemeba.pdfIn PDF document text
    • http://dr-onesrl.com/userfiles/files/reruzo.pdfIn PDF document text
    • http://lahma.pl/_u/userfiles/file/71526865148.pdfIn PDF document text
    • https://confeccionesruiz.cl/UserFiles/File/bobeneditozegifapirot.pdfIn PDF document text
    • https://bellcera.60km.com/upload/files/varosatomojiwatef.pdfIn PDF document text
    • https://medtek.vn/storage/file/tined.pdfIn PDF document text
    • http://massvt.sk/editor_uploads/system/files/20729203752.pdfIn PDF document text
    • http://nano-vip.com/ckfinder/userfiles/files/51429643174.pdfIn PDF document text
    • https://vargyasnekonyveles.hu/kepek/other/file/kakut.pdfIn PDF document text
    • https://wangwangcamp.com/uploads/files/202109240610256743.pdfIn PDF document text
    • http://vigova.com/Images_upload/files/27358447415.pdfIn PDF document text
    • https://rtquery.reitoken.org/Coaching123/images/files/modevotuxamagojap.pdfIn PDF document text
    • http://tetobox-budapest.hu/uploads/files/saladorojutaludoselonuse.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_off0000b46e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB46E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cc80.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCC80 17676 bytes
SHA-256: 99305d2b57d4e59f8f583cede28b3739b0d418f3006ecc7e0ec5d1da2d62c20c
font_02_sfnt_off0000f9b7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9B7 10492 bytes
SHA-256: 0529edc1b4b8ea3f6aa473799d94a43800bdcd694e581ee8b8c87a90240bd24a