Malicious PDF — malware analysis report

Static analysis result for SHA-256 a4b8496773b03acd…

MALICIOUS

PDF

83.0 KB Created: 2021-09-21 06:49:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 6a79579693d3a9f9642440a3932d1663 SHA-1: f42eec8a0bca384c7edf0b8443aeafe38891937c SHA-256: a4b8496773b03acd2bfe6191564e3d12e826d55e644fb0e9cc7493e8b49ce0bb
156 Risk Score

Malware Insights

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

The file was identified as malicious by ML classifiers and ClamAV, indicating it is a phishing or trojan delivery mechanism. It functions as a link farm, with numerous embedded URLs pointing to external sites, some of which are hosted on compromised WordPress installations or disposable domains. This suggests an attempt to lure users to malicious content or download further payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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://synerhu.ru/uplcv?utm_term=fahrenheit+pdf+451 PDF link annotation
    • https://texasbordervolunteers.org/userfiles/file/87240609057.pdfIn PDF document text
    • http://www.aportecnica.com/imagenes/editor/file/39685090124.pdfIn PDF document text
    • http://andrenickels.de/ckfinder/userfiles/files/koguzovoniwosakatuxodesu.pdfIn PDF document text
    • http://www.cuerpomenteyespiritu.es/wp-content/plugins/formcraft/file-upload/server/content/files/161316374d4b5d---90658997178.pdfIn PDF document text
    • http://sushiyaslo.com/uploads/files/medagusagumitupisakel.pdfIn PDF document text
    • https://www.notusweb.com.br/ckeditor/ckfinder/userfiles/files/titoneginexigatakot.pdfIn PDF document text
    • https://eletroluz-al.com/_IMG/img_internas/file/9781725015.pdfIn PDF document text
    • http://thoitrangvabaoho.com/Images_upload/files/19015464963.pdfIn PDF document text
    • https://hoangnhataudio.vn/media/files/bunewit.pdfIn PDF document text
    • http://alacarte-grafik.de/userfiles/file/13795006610.pdfIn PDF document text
    • https://servicepapik.ro/files/jumulosidevubopi.pdfIn PDF document text
    • http://geodavidepini.it/userfiles/files/59366264772.pdfIn PDF document text
    • http://skrabl.pl/www/rpbd/fck/file/tapujabewi.pdfIn PDF document text
    • http://pusancard.com/userData/board/file/10445865514.pdfIn PDF document text
    • http://lisahyatthealth.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138e1807574a---29646489193.pdfIn PDF document text
    • http://www.norestim.ro/wp-content/plugins/formcraft/file-upload/server/content/files/161489fef73a00---godawaladoposo.pdfIn PDF document text
    • http://distant-property.ru/fck_editor_files/files/mekuxitik.pdfIn PDF document text
    • https://beaufortbond.com/wp-content/plugins/super-forms/uploads/php/files/e25b4be57f00af68f8207c6b3778b506/nobimamabirobe.pdfIn PDF document text
    • http://test-immo.com/file/17868655039.pdfIn PDF document text
    • https://s-oil.hoakhanh.vn/uploads/image/files/fefugalo.pdfIn PDF document text
    • https://hasekei.jp/userfiles/file/21651893500.pdfIn PDF document text
    • https://www.ciabrini-immobilier.com/wp-content/plugins/super-forms/uploads/php/files/alb8vd29hhk4mn1eg7o1ju75t2/sefovupudiputej.pdfIn PDF document text
    • http://all-paca.com/ckeditor/ckfinder/core/connector/php/uploads/files/84436084812.pdfIn PDF document text
    • http://canadapremiumlubes.com/survey/userfiles/files/54730282328.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_off0000deb8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDEB8 19140 bytes
SHA-256: 3a6bc4356c0a95c6039f0256bf2a7d2a6f9b97513de2fc7f7c5caabb49f73e31
font_01_sfnt_off00010f02.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10F02 10504 bytes
SHA-256: 17fe387cfaee013d9755ef013b59211df360104776f1cb405255d2d5a08a5eb3
font_02_sfnt_off000126e1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x126E1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1