Malicious PDF — malware analysis report

Static analysis result for SHA-256 913d8af68de3b77b…

MALICIOUS

PDF

80.4 KB Created: 2021-03-02 22:16:04 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-23
MD5: 082197d47d4bde66b7372ae3d9253949 SHA-1: 090b3762826469df9f3078a9df73b4f4d977fc89 SHA-256: 913d8af68de3b77b8da2b2e4930e1bf49a9d2d9d89f4c1cbd9d083c2243ed616
184 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF contains numerous embedded URLs, with several heuristics flagging it as a malicious redirector and link farm. The ML classifier and ClamAV detection strongly indicate malicious intent. The document body, though heavily obfuscated, contains metadata suggesting it was generated by wkhtmltopdf, a tool often used to create malicious PDFs that redirect users to external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9995

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
  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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.
  • 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://yafferge.ru/123?utm_term=what+is+the+hardest+algebra+question In PDF document text
    • http://reassurez-moi-fr.info/v_t_bhattathiripad_books2jz79.pdfIn PDF document text
    • http://ductsunlimitedins.com/household_expense_spreadsheetillqp.pdfIn PDF document text
    • https://cdn.sqhk.co/kulobibab/AnghghO/dune_2000_series_review.pdfIn PDF document text
    • http://revershjtb.site/64040085705no32u.pdfIn PDF document text
    • http://health-top.ru/34824988262jsmup.pdfIn PDF document text
    • https://cdn.sqhk.co/xidatelo/hjhTage/mivubudodizixufitonodi.pdfIn PDF document text
    • http://yognat.space/low_histamine_food_listscs4a.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4369516/normal_5fe8a4a8e11c2.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4491969/normal_6000ef8551481.pdfIn PDF document text
    • https://cdn.sqhk.co/nozedimasav/R9hjghT/30387491822.pdfIn PDF document text
    • https://cdn.sqhk.co/motuwezelu/hjnhjhj/zexakoridemakawidaje.pdfIn PDF document text
    • https://cdn.sqhk.co/vobevufubito/iijgjad/tempest_pirate_action_rpg_premium_mod_apk_revdl.pdfIn PDF document text
    • https://cdn.sqhk.co/lotivadafe/fdihhjd/68208418824.pdfIn PDF document text
    • http://rubyshup.space/dipenalarorurumewutefokeskvjdu.pdfIn PDF document text
    • http://libertinemodels.com/manorama_calendar_2020lscbz.pdfIn PDF document text
    • https://cdn.sqhk.co/vivokunavu/g0igEOS/xekofuresijisovuv.pdfIn PDF document text
    • https://cdn.sqhk.co/vikeguzag/nidiiao/sijivigosinuvanos.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4412159/normal_5ff10e6c2d87f.pdfIn PDF document text
    • https://cdn.sqhk.co/kisasizaro/jevdjfl/funny_gifts_for_friends_diy.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4474169/normal_5fcfec6ad46d3.pdfIn PDF document text
    • http://sqrab.top/black_and_decker_chv1410l_vs_chv1410l322dv5r.pdfIn PDF document text
    • https://cdn.sqhk.co/fezifoxunif/igesooM/choeaedol_kpop_idol_ranks_app.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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://scripts.sil.org/OFLIn 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_off0000e8a3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE8A3 5364 bytes
SHA-256: 061616e8a1a5f1b7d4a8042069666dd4fdf85788758461fdaf157b4839877c86
font_01_sfnt_off0000fada.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFADA 10376 bytes
SHA-256: ce35c0e031e98cb6725e4d6c41536b9343215e5f3530116553fb21f195ccde72
font_02_sfnt_off00011e95.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E95 16188 bytes
SHA-256: 66d0f489606d9c5ff4050b9b55468195e34b06defb7ed2c6495d21f9854cc902