Malicious PDF — malware analysis report

Static analysis result for SHA-256 b41238e3a7f7b885…

MALICIOUS

PDF

80.6 KB Created: 2021-09-19 12:53:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 4ff8156482e89c8bcc5861cb52730d8e SHA-1: 4f7da96fedf42f19be3e1e191bbea5f043f9717d SHA-256: b41238e3a7f7b8854b9ae904e874d177b03341ad874ed9ef61b97204f6b07258
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. Heuristics indicate it functions as a link farm, directing users to numerous distinct domains, one of which is `tunhuaduytan.com`. The presence of embedded URLs and the nature of the heuristics suggest the document is designed to redirect users to potentially malicious sites for further exploitation.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://tunhuaduytan.com/upload/userfiles/files/xonidisolazu.pdf In PDF document text
    • http://wx-bm.cn/upload/ckimg/files/202109051820503639.pdfIn PDF document text
    • http://worldnaturalfood.com/image/upload/File/xurefonoselaza.pdfIn PDF document text
    • https://villanakarin.com/userfiles/files/rulozuvifujokujireme.pdfIn PDF document text
    • http://obkladacstvikolar.com/content/59040477000.pdfIn PDF document text
    • http://ekouklid.eu/UserFiles/file/63097013868.pdfIn PDF document text
    • https://iasvn.org/Images_upload/files/befedijevumabasasipu.pdfIn PDF document text
    • https://sf-tfi-pgu.uz/wp-content/plugins/super-forms/uploads/php/files/e382890eb5d30db460d376d2ac7247fc/89598856396.pdfIn PDF document text
    • http://ikkosushi.com/uploads/files/kegomesikore.pdfIn PDF document text
    • http://www.binghan.my/userfiles/file/13523200779.pdfIn PDF document text
    • https://uaqbakery.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614633a1f053d---dixawosimidafo.pdfIn PDF document text
    • http://zeci.nl/im/image/pubovi.pdfIn PDF document text
    • https://maintogelonline.bet/contents/files/polareguwego.pdfIn PDF document text
    • http://kanchanaspa.com/ckfinder/userfiles/files/54488241282.pdfIn PDF document text
    • https://penzion-palice.cz/content/perevotijorodonan.pdfIn PDF document text
    • https://rajatotogroup4.com/contents/files/40702446740.pdfIn PDF document text
    • https://postelezmasivu-ostrava.cz/ckfinder/userfiles/files/febofub.pdfIn PDF document text
    • https://icnj.net/ckeditor/ckfinder/userfiles/files/28179993963.pdfIn PDF document text
    • http://ingegnasrl.com/userfiles/files/xodizukozevijofiv.pdfIn PDF document text
    • http://smartvoicecom.com/userfiles/78257828034.pdfIn PDF document text
    • http://www.cerel.eu/images/wyswig_images/file/58060516243.pdfIn PDF document text
    • http://tlxzkj.com/uploads/file/111743526041.pdfIn PDF document text
    • http://a-mega.ua/images/uploads/file/jalipi.pdfIn PDF document text
    • http://studiomarcheluzzo.it/userfiles/files/60092704195.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/fzgW7-mxBc0/uplcv?utm_term=fire+engine+simulator+mod+apkPDF 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_off0000cd3a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCD3A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e551.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE551 10904 bytes
SHA-256: fb00a8b0ee606dac6d72cda707d3a17f011b729f2b873f4f9e704c1bfaf7a3ef
font_02_sfnt_off0000fe51.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE51 20872 bytes
SHA-256: 9605753bec0371bf17a67696d56b68967db588e34633b63fb8d0fd9eff148635