Malicious PDF — malware analysis report

Static analysis result for SHA-256 a4e0b20561ec73c4…

MALICIOUS

PDF

74.8 KB Created: 2021-10-04 16:20:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: a16475f9564b18f04a6a11f2a96081fb SHA-1: d1d66c80d8c8d451dce8e985352059b02b6cc236 SHA-256: a4e0b20561ec73c48a648c89484710151573e570299d7ea28305753863093551
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, containing numerous embedded URLs pointing to other PDF files hosted on various domains. The document body is heavily obfuscated and unreadable, suggesting it is not intended for direct user interaction but rather to facilitate redirection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

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://californiaoptionsrealestate.com/wp-content/plugins/super-forms/uploads/php/files/806b35eb85f62cfaee121b5b3ee4bf78/77467418148.pdf In PDF document text
    • http://gorisum.net/fckeditor/upload_file/file/12026898282.pdfIn PDF document text
    • http://missteenqueenuk.com/userfiles/file/62515244750.pdfIn PDF document text
    • https://dp-engineers.com/admin/userfiles/file/17633729229.pdfIn PDF document text
    • http://pomelieagency.com/userfiles/files/76238847567.pdfIn PDF document text
    • http://pjteam.hu/uploads/48802665463.pdfIn PDF document text
    • http://www.ufolep-69.com/contenus/files/77592174307.pdfIn PDF document text
    • http://ccsilver.kr/files/fckeditor/file/312815154615a7b818e10d.pdfIn PDF document text
    • https://arch.ua/ckfinder/userfiles/files/70972945172.pdfIn PDF document text
    • https://www.multilandtours.com/assets/ckfinder/userfiles/files/worusivozoliduvivuwoju.pdfIn PDF document text
    • https://paardenwelzijnscheck.nl/app/webroot/files/ckeditor_files/files/34211285353.pdfIn PDF document text
    • https://larrialdiak.es/files/galeria/files/kuzifopazavikepafiji.pdfIn PDF document text
    • http://arisutour.com/ckupload/files/jegujewowif.pdfIn PDF document text
    • http://olympiad-bigben.ru/ckfinder/userfiles/files/nuvomujaxiw.pdfIn PDF document text
    • https://voicelux.ru/wp-content/plugins/super-forms/uploads/php/files/6acf61698d5a9ea1b6c96618bc95aa44/rulunomixuzanivivetuzu.pdfIn PDF document text
    • https://samsungdvmklima.com/upload/ckfinder/files/subobawibavufogawasamu.pdfIn PDF document text
    • http://asude.istanbul/ck_images/files/nadipopa.pdfIn PDF document text
    • http://mizuho-co.net/file/ck/files/lidisunobo.pdfIn PDF document text
    • http://art-lan.ru/uploads/assets/file/51255416087.pdfIn PDF document text
    • https://gencshoworganizasyon.com/upload/ckfinder/files/bidaxojopodolikagutivama.pdfIn PDF document text
    • https://marmetal.cevhertemizlik.com/userfiles/files/25473352985.pdfIn PDF document text
    • http://studiomontironi.eu/userfiles/files/64374372069.pdfIn PDF document text
    • http://rutka.pl/media/upload/files/eaf578013e18c11bdf025bcb4e4497a3.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BkSY9tpko7c/uplcv?utm_term=cast+of+the+legend+of+bruce+leePDF 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_off0000bc50.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBC50 10936 bytes
SHA-256: ea68929a3d29ba2f1f85599db5f6343740234e47665517ac3a9f8396cb5fdd4c
font_01_sfnt_off0000d568.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD568 18608 bytes
SHA-256: f1d2b960c6b25da091cb7c2ef450f84bd065d3c3a2d977c07fde854383366b8b
font_02_sfnt_off00010518.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10518 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1