Malicious PDF — malware analysis report

Static analysis result for SHA-256 4cf4eac2e7e57a96…

MALICIOUS

PDF

84.6 KB Created: 2021-09-21 01:25:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: a7233e6cd113fc0ccd539db45f497566 SHA-1: 529ce675aeb9f8dc7c76889b9500dba25dd9a25b SHA-256: 4cf4eac2e7e57a96982dc407b79bc9f7d75ad83aa0236d0f26788e1a7ad94cd3
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 User Execution: Malicious File

The PDF contains numerous embedded URLs, many of which point to compromised CMS upload directories or disposable hosting, suggesting a link farm or SEO poisoning tactic. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution. No scripts were extracted, and the document body was unreadable, limiting the analysis of specific user lures.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9972

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 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.
  • 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://stellar.ru/ckfinder/userfiles/files/66986355173.pdf In PDF document text
    • https://susta.vn/userfiles/file/50971446200.pdfIn PDF document text
    • https://sibservis.com/ckfinder/userfiles/files/fesemevovafopiwusas.pdfIn PDF document text
    • http://sissonne.hu/editor_up/90308913925.pdfIn PDF document text
    • http://flightshop.jp/images/blog/file/12446771907.pdfIn PDF document text
    • http://fpempresa.cen.es/userfiles/files/70040996279.pdfIn PDF document text
    • https://zoomkish.com/basefile/zoomkishcom/files/vebofofu.pdfIn PDF document text
    • http://vanhacollection.com/images/files/11875672211.pdfIn PDF document text
    • http://elliptical-trainers.ru/ckfinder/userfiles/files/54212755534.pdfIn PDF document text
    • http://www.abcklima.hu/data/editorfile/50440839520.pdfIn PDF document text
    • https://bilbox.es/wp-content/plugins/super-forms/uploads/php/files/24fabb82a4a56f7668542712e40185d9/supesepom.pdfIn PDF document text
    • https://autosofortkauf.ch/wp-content/plugins/super-forms/uploads/php/files/kv8q76jqbgdgjr9e8fhfsnk4d4/zotovalomevuw.pdfIn PDF document text
    • https://borderpak.com/wp-content/plugins/super-forms/uploads/php/files/1deaf3ad3d87e4ba3de023f985aeb050/junosusuvenajaru.pdfIn PDF document text
    • http://www.cuadernos.in/wp-content/plugins/formcraft/file-upload/server/content/files/16141bc710cdb7---68108299788.pdfIn PDF document text
    • http://bukharaalpharetta.com/sites/default/files/file/6671889222.pdfIn PDF document text
    • http://hocikto.info/userfiles/file/dikitaruwuzimilasitiw.pdfIn PDF document text
    • http://ats-dz.com/userfiles/file/jaxoxalaj.pdfIn PDF document text
    • http://www.slenderclub.cz/ckfinder/userfiles/files/55989502523.pdfIn PDF document text
    • http://xn--nellieskche-0hb.de/userfiles/file/litemikakomiguvomirun.pdfIn PDF document text
    • https://mercedesmazo.es/wp-content/plugins/formcraft/file-upload/server/content/files/1613bc66030519---jexamekutizivagojefiw.pdfIn PDF document text
    • http://elenasteele.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138ea1fe4e8d---zowofujomaropoxobake.pdfIn PDF document text
    • http://bacvietexpress.com/upload/userfiles/files/71541836720.pdfIn PDF document text
    • http://lexxyin.net/files/fckeditor/file/lezapiwalixama.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BkSY9tpko7c/uplcv?utm_term=vsco+video+editor+mod+apk+downloadPDF 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://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_off0000e8b9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE8B9 10888 bytes
SHA-256: 8a9ff3076f985b5c79c089ead13e7dd4e59ff6331e8d57d8cd68dd635d484787
font_01_sfnt_off000101f9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x101F9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011a0b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11A0B 18760 bytes
SHA-256: 8f905ae6b2d1113251cf31e02cdfbbdceac242bbde38255e9b130dc437c91c3f