Malicious PDF — malware analysis report

Static analysis result for SHA-256 39b71168ad1d7857…

MALICIOUS

PDF

88.6 KB Created: 2021-09-02 12:08:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: c41a5d3a148a1b97d9cce44478487eaa SHA-1: c293ccc30bd1569a62b9fb020c135ee5d782a8a9 SHA-256: 39b71168ad1d7857a8d5e4449a7574aa8a45fb804bf7cd6fdcf58a2c45b73b7d
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

This PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and by an ML classifier as malicious. It contains numerous external URIs, many of which point to compromised WordPress upload directories or disposable hosting, suggesting a link farm designed to distribute malicious content or phish users. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, indicating it's not intended for direct user reading but rather as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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 https://medvor.ru/uplcv?utm_term=nouns+singular+and+plural+forms+pdf PDF link annotation
    • http://www.nuricomuvakfi.org/wp-content/plugins/super-forms/uploads/php/files/v87c43pjs9277oh07rp91pp3s4/bovef.pdfIn PDF document text
    • http://zamokugrofa.sk/admin/fckeditor/file/39739292571.pdfIn PDF document text
    • https://www.pferde-fuer-unsere-kinder.de/wp-content/plugins/formcraft/file-upload/server/content/files/16098db15a9b5f---xekep.pdfIn PDF document text
    • http://dorisemitchell.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/zeleb.pdfIn PDF document text
    • http://dlmberatung.ch/userfiles/files/66238575668.pdfIn PDF document text
    • http://kindervakantieweekdeurne.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16070522ea0f09---33512322122.pdfIn PDF document text
    • http://ipjanah.ir/wp-content/plugins/super-forms/uploads/php/files/2ds6rlbenbpk9g8vklhvmhc0o0/xefozalasobamasalubif.pdfIn PDF document text
    • https://xylemleads.com/userfiles/file/52815612276.pdfIn PDF document text
    • http://www.driftime.ee/wp-content/plugins/formcraft/file-upload/server/content/files/1607b54c10cb16---72408900050.pdfIn PDF document text
    • http://samnakthodrahassob.com/userfiles/file/jasevexoxasibad.pdfIn PDF document text
    • http://resheto.ru/users_images//fck/file/28505883563.pdfIn PDF document text
    • http://www.heksan.com.pl/file/75421326057.pdfIn PDF document text
    • https://hinodanang.com/uploads/image/files/22927946782.pdfIn PDF document text
    • http://etcad.net/np/upfile/file/48836766322.pdfIn PDF document text
    • http://staging.impactredevelopment.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608444418ab86---pomaweru.pdfIn PDF document text
    • https://www.areatransfers.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607a6f352d4c7---zixofuvunotimanevabalev.pdfIn PDF document text
    • http://bighost.vn/uploads/userfiles/file/87697159066.pdfIn PDF document text
    • http://www.sunarsurdurulebilir.com/wp-content/plugins/super-forms/uploads/php/files/ih1lb7nr5rrmr5jnlrovnkt7f4/3741152502.pdfIn PDF document text
    • http://www.hollyskauaicondo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607dd9f942775---2895091425.pdfIn PDF document text
    • https://www.physioaktivkramer.de/wp-content/plugins/formcraft/file-upload/server/content/files/16090db9b19f51---gedozanexepezetej.pdfIn PDF document text
    • https://iveducentar.com/uploads/assets/file/tisiwifunuxezebiwig.pdfIn PDF document text
    • http://xn--e1aaafipco3bk8gra3b.xn--p1ai/upload_picture/file/72179951982.pdfIn PDF document text
    • https://jennysbooks.com/wp-content/plugins/super-forms/uploads/php/files/e615e558da747116869254d9dc56a908/wiwawoxajugog.pdfIn PDF document text
    • http://dok-vo.ru/userfiles/file/penepezebobevasejugebape.pdfIn PDF document text
    • https://agsposure.org/wp-content/plugins/super-forms/uploads/php/files/a7941145c36cc04a1f85acb2bb1b7200/67458584949.pdfIn PDF document text
    • 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_off0000f629.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF629 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010e3b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10E3B 17612 bytes
SHA-256: 7174648562f37d403c298bfdac8fd71c097d1bc59ae4b40a9b456f3bc59924d8
font_02_sfnt_off00013c4c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13C4C 10688 bytes
SHA-256: d1630beb54fb86adf064e9275b2e469986b1a6ee9ae6b13caaa882da68eed6be

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