Malicious PDF — malware analysis report

Static analysis result for SHA-256 631991afb3b1d1b7…

MALICIOUS

PDF

72.6 KB Created: 2021-08-28 04:24:03 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 82305d7d5dae0c8bc78385026776b798 SHA-1: 44c11d11ff71bc416c1047bd09b3494349e49c9e SHA-256: 631991afb3b1d1b7a07795fedbafcf66fef5bd62acd710a7716afbf38ebf1ac6
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs pointing to compromised websites, indicating a link farm designed to redirect users to malicious content. The ML classifier strongly flagged this PDF as malicious, and heuristics identified it as a link farm on disposable hosting. While no scripts were directly extracted, the nature of the embedded URLs suggests a potential for further malicious activity upon user interaction.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

Heuristics 5

  • 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://nomylo.ru/uplcv?utm_term=line+and+load PDF link annotation
    • https://ipssecurityconsultants.com/ckfinder/userfiles/files/wixavididilukanaguboluw.pdfIn PDF document text
    • https://mandalaconfeccao.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160ec9c36004bf---97227065190.pdfIn PDF document text
    • https://bloomland.com/sites/bloomland.com/files/64295107977.pdfIn PDF document text
    • https://www.chinacimctrailer.com/wp-content/plugins/super-forms/uploads/php/files/516f07d88309b5cea497d84a1166d592/75852098649.pdfIn PDF document text
    • http://avs-market.ru/admin/ckfinder/userfiles/files/73969521980.pdfIn PDF document text
    • https://lostsoulsmemorialnj.org/wp-content/plugins/super-forms/uploads/php/files/c63ee277893d2a9176bda29842d8e89c/navuzugimuraf.pdfIn PDF document text
    • https://vidolamerica.org/wp-content/plugins/super-forms/uploads/php/files/e7eca4af35623be76884dac37661ad7b/11904613473.pdfIn PDF document text
    • http://famcareconnect.org/wp-content/plugins/formcraft/file-upload/server/content/files/160c3b21147951---77670797001.pdfIn PDF document text
    • https://www.davinci.dk/wp-content/plugins/formcraft/file-upload/server/content/files/1611fa5257cb59---76669556313.pdfIn PDF document text
    • https://fotobolfestmeny.hu/mvc/userfiles/file/ledazitigozukub.pdfIn PDF document text
    • https://asigurareingermania.ro/wp-content/plugins/super-forms/uploads/php/files/8q655p8r5kmt4k6us9fpkd26dp/nalutaruzovetidinefo.pdfIn PDF document text
    • https://bevillelecomte.ovh/ckfinder/userfiles/files/xapujelukapepabibovivir.pdfIn PDF document text
    • http://www.opencalgary.org/wp-content/plugins/formcraft/file-upload/server/content/files/1607bf50834ade---fixifolukofomivusurefez.pdfIn PDF document text
    • http://baltic-rt.ru/ckfinder/userfiles/files/59148258329.pdfIn PDF document text
    • http://www.korayozelguvenlik.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608003655b2a5---83275702062.pdfIn PDF document text
    • http://wsm.hk/images/uploadfiles/file/66281170857.pdfIn PDF document text
    • http://kaufdeinauto.de/wp-content/plugins/formcraft/file-upload/server/content/files/16076ed0c0fc05---3347398231.pdfIn PDF document text
    • http://tradeweb.es/userfiles/file/nobigeme.pdfIn PDF document text
    • https://www.sevgiliyevideo.net/wp-content/plugins/formcraft/file-upload/server/content/files/160a9c414a1764---11144443393.pdfIn PDF document text
    • http://hanhthien.net/uploads/file/63256203908.pdfIn PDF document text
    • http://cinstech-inspect-survey.com/fckeditor_userfiles/file/kesuvakitigube.pdfIn PDF document text
    • http://luatsubienhoa.com/upload/ck/files/misasisufomuso.pdfIn PDF document text
    • https://krimgranit.ru/wp-content/plugins/super-forms/uploads/php/files/bf7d3a02a7a882f5ccbfde119f8c79d8/lasadinideja.pdfIn PDF document text
    • http://sbstroy53.ru/img/files/kazinudonesijuvuzux.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_off0000bcac.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBCAC 16956 bytes
SHA-256: ce633188f8f0420a3b1bf4538a468b24e98c05161d906d6a96d75d11da1a3804
font_01_sfnt_off0000e70d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE70D 9832 bytes
SHA-256: bf223e9679c1dbf0b87aac532ec2b8a5ef069dcb1803fd6ee42f644915175488
font_02_sfnt_off0000fca4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFCA4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1