Malicious PDF — malware analysis report

Static analysis result for SHA-256 2d88c35546a7375a…

MALICIOUS

PDF

75.2 KB Created: 2021-09-04 04:06:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 26e49751a6eff1ecdba0075e1decdb09 SHA-1: dcf19a19f242351ecf4d87700b574df62e46d9e9 SHA-256: 2d88c35546a7375af33689b254f9af27692078fe1bf63848e97c671855c0e794
164 Risk Score

Malware Insights

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

The sample is a PDF document flagged by ML classifiers and ClamAV as malicious. It functions as a link farm, containing numerous URLs pointing to various websites, some of which are hosted on compromised WordPress installations. The document body is heavily obfuscated and unreadable, but heuristic analysis indicates the presence of urgency lures. The primary attack pattern involves directing users to potentially malicious external sites via these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9827

Heuristics 7

  • 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.
  • Urgency / deadline lure low SE_URGENCY_LURE
    Document contains urgency or deadline language ('account will be terminated', 'action required within 24 hours', etc.) — useful context, but low-signal without other findings
  • 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://beldapin.com/calisma2/files/uploads/kufezurugajilit.pdf In PDF document text
    • https://virtualpulse.eu/UserFiles/file/13364616800.pdfIn PDF document text
    • https://amenagementsoleil.com/wp-content/plugins/formcraft/file-upload/server/content/files/160782a4c84e31---zejakiruje.pdfIn PDF document text
    • https://trungtammatnamviet.vn/upload/files/nenujiluriruzulosinagow.pdfIn PDF document text
    • http://robotsuk.com/luckingbros.co.uk/userfiles/files/madijefojoza.pdfIn PDF document text
    • http://e3edu.vn/public/ckfinder/core/connector/php/connector.phppublic/uploadsfiles/37980801092.pdfIn PDF document text
    • https://www.makathastaliklari.net/wp-content/plugins/formcraft/file-upload/server/content/files/160747759447e8---380370147.pdfIn PDF document text
    • https://pendekaremas.com/contents//files/92635021738.pdfIn PDF document text
    • https://chocoinmobiliario.com/wp-content/plugins/super-forms/uploads/php/files/bc7391f20ca79562fd2723a6861e0781/xutiwaxetapolavixudixejur.pdfIn PDF document text
    • http://reklamavysocina.cz/UserFiles/File/18787197626.pdfIn PDF document text
    • https://webgirls-studio.com/wp-content/plugins/formcraft/file-upload/server/content/files/160f2548983430---suzakagesisebetemol.pdfIn PDF document text
    • http://ergo-logo-bamberg.de/userfiles/file/tinirumadudal.pdfIn PDF document text
    • https://avantkart.com/wp-content/plugins/super-forms/uploads/php/files/uneg66ci6viedn21k1ta2vqrkj/19764994998.pdfIn PDF document text
    • https://jclifeschools.org/wp-content/plugins/super-forms/uploads/php/files/7d04c0f682776a2b35632494cc1d306c/pulaf.pdfIn PDF document text
    • http://kco.su/userfiles/file/gimafanoxegugunosut.pdfIn PDF document text
    • http://aylincinarli.com/fckfiles/file/98475572018.pdfIn PDF document text
    • https://certifiedmoversinc.com/wp-content/plugins/super-forms/uploads/php/files/00a9ff69bd1cf5bbe7ece2ebe3419ffc/37794624919.pdfIn PDF document text
    • http://yuha.be/_files/file/94762221464.pdfIn PDF document text
    • https://bititechnika.com/uploads/file/wafebifepu.pdfIn PDF document text
    • http://ping-property.com/user_img/files/fidavadavad.pdfIn PDF document text
    • https://zapcdn.space/web/img/podborky/files/97774398125.pdfIn PDF document text
    • http://begemot-rus.com/uploadfiles/file/2021071712131173499.pdfIn PDF document text
    • http://krindustria.com.br/site/wp-content/plugins/formcraft/file-upload/server/content/files/160ca3d4ee7274---46273401909.pdfIn PDF document text
    • http://cuacuonnhaxuongbinhduong.com/upload/files/ruramaturatov.pdfIn PDF document text
    • http://xn--e1aaafipco3bk8gra3b.xn--p1ai/upload_picture/file/nitivowez.pdfIn PDF document text
    • http://chinhsuasolieu.com/media/files/kogivixabuvuzejagojasav.pdfIn PDF document text
    • http://ednak.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608b1392f1bfc---51031140313.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=speak+up+1+pdfPDF 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_off0000c73c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC73C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000df4e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF4E 16164 bytes
SHA-256: de0c4f6cbc809f2f1923b1d8a4f35f06b9a827d54c41aba6e4f03abe104b034a
font_02_sfnt_off000108d3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x108D3 10080 bytes
SHA-256: 05d6c420661670034ba43a48c460393cbde45e429d9584a996400e7f262d76da