Malicious PDF — malware analysis report

Static analysis result for SHA-256 b4c38a9562d5de43…

MALICIOUS

PDF

71.4 KB Created: 2021-09-30 23:15:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 097656b0603be9028d4f9d2e245f7713 SHA-1: 752a351f9ff0170b23d71ccaf654cd30b288e75a SHA-256: b4c38a9562d5de43849631c33aaf5c0edaef83fee2fb240f3aae393ff11a92ce
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to numerous distinct hosts, with one URL explicitly containing 'free fire hacking app' suggesting a lure. While no scripts were directly extracted, the PDF structure and link farm behavior are indicative of a phishing or malware distribution attempt, likely initiated via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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 http://daiduongmetal.com/uploads/ckfinder/files/noxidumak.pdf In PDF document text
    • https://mudraconsultancy.com/uploads/files/81523685424.pdfIn PDF document text
    • http://angelcabrera.com/FCKfiles/file/wozigegizebifokepal.pdfIn PDF document text
    • https://fond.ru/userfiles/file/zetoberon.pdfIn PDF document text
    • https://alcc.vn/wp-content/plugins/super-forms/uploads/php/files/6smae9anj8pli38jeal4h7ila9/63088220070.pdfIn PDF document text
    • http://cachnhietcacham.vn/Images_upload/files/zufafo.pdfIn PDF document text
    • https://tsolisp.com/files/file/50374632008.pdfIn PDF document text
    • http://thegioidahoacuong.com/uploads/image/files/27151622219.pdfIn PDF document text
    • https://pataniforum.com/admin/jquery/ckfinder/userfiles/files/45924859895.pdfIn PDF document text
    • http://irinabailey.com/upload/files/pijomemum.pdfIn PDF document text
    • https://selapro.com.au/application/third_party/ckfinder/userfiles/files/togedopogubawowirupep.pdfIn PDF document text
    • http://snap-drone.com/userfiles/file/52123747229.pdfIn PDF document text
    • https://havilahbuilders.com/userfiles/file/kiwijavufakonameden.pdfIn PDF document text
    • http://baigeleather.com/userfiles/file/57048519806.pdfIn PDF document text
    • http://wksx.top/images/userfiles/file/rigabelinugejogizafi.pdfIn PDF document text
    • https://chowdhurytourism.com/ckfinder/userfiles/files/kefebetorixebini.pdfIn PDF document text
    • http://vmkmsz.hu/userfiles/file/96070872029.pdfIn PDF document text
    • https://directorvincentchow.com/fck_filemanager_upload/file/kilubebudulix.pdfIn PDF document text
    • http://saint-party.com/media/file/72034262494.pdfIn PDF document text
    • http://jiangsutravel.kr/userfiles/files/20210909_171429.pdfIn PDF document text
    • https://gbagencement.fr/uploads/file/12893585060.pdfIn PDF document text
    • https://briljant-maleri.se/UserFiles/files/413098092.pdfIn PDF document text
    • https://sbsoftware.ro/admin/userfiles/file/bifozu.pdfIn PDF document text
    • https://synodradomski.pl/userfiles/file/senozifulemumeguv.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1KS0DP0cxss/uplcv?utm_term=free+fire+hacking+app+luluboxPDF 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_off0000b0ab.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB0AB 18584 bytes
SHA-256: e4d92377cc1c141351e06d501f9314e570d5236fd6b30499ff0c6ef8366ac22c
font_01_sfnt_off0000df58.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF58 10904 bytes
SHA-256: f6e9480475fc8b81d310181bdfbb79498e07142ab0fc26bc06922d3ca70bdf69
font_02_sfnt_off0000f839.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF839 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1