Malicious PDF — malware analysis report

Static analysis result for SHA-256 21d8fef8fff995b4…

MALICIOUS

PDF

78.0 KB Created: 2021-10-05 10:21:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 7364267c0c042265e2319a4ea5fbad77 SHA-1: 4ae47a3a100619db47baad543b9ba827087677a7 SHA-256: 21d8fef8fff995b46e02b0e3e73bfc307d8bc7f46db3199459fc74cd90783318
156 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many pointing to compromised CMS uploads or disposable hosting, indicating a link farm designed to lead users to malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware delivery. No scripts were extracted, but the structure and URL patterns are indicative of a malicious PDF.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

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://altaamir.ipixpms.com/Rapport/public/assets/ckfinder/userfiles/files/73613441795.pdf In PDF document text
    • https://ptkas.com/kingkong/userfiles/files/1836476121.pdfIn PDF document text
    • http://mensagemcrista.com.br/ckfinder/userfiles/files/48727222324.pdfIn PDF document text
    • http://www.jesuseslaroca.org/wp-content/plugins/formcraft/file-upload/server/content/files/161564e103afd5---tizuroxoze.pdfIn PDF document text
    • https://kamwalibais.com/userfiles/file/78933181886.pdfIn PDF document text
    • http://linpus.com/app/webroot/userfiles/files/valekudugujebogunujufal.pdfIn PDF document text
    • https://congtydaihai.com/upload/files/lotadenadilikawolaris.pdfIn PDF document text
    • http://carszana.com/image/upload/File/dotup.pdfIn PDF document text
    • http://twilaw.com/files/files/wigukupo.pdfIn PDF document text
    • https://cutletsmeat.com/wp-content/plugins/formcraft/file-upload/server/content/files/16148553b8df4c---20469589333.pdfIn PDF document text
    • http://www.nuricomuvakfi.org/wp-content/plugins/super-forms/uploads/php/files/rgd4l31c09a843j40opl683lk4/suwipofukanegofopum.pdfIn PDF document text
    • http://abwnickersonplaza.com/uploads/files/zupuxizogirofiwefatewus.pdfIn PDF document text
    • https://khonggiansangtao.com/platformecom/img/upload/file/selofapuvuzagep.pdfIn PDF document text
    • http://sinoscaform.com/upload/ckimg/files/202109210733299008.pdfIn PDF document text
    • https://www.davinci.dk/wp-content/plugins/formcraft/file-upload/server/content/files/161395cb4a467a---zuxowugob.pdfIn PDF document text
    • http://yusungchart.com/userData/board/file/rumekodofipuzijuwobum.pdfIn PDF document text
    • http://daehwa.info/uploaded/file/8942111564.pdfIn PDF document text
    • https://girilawfirm.com/content_files/files/zegoxexunojetivapawuwu.pdfIn PDF document text
    • http://robertwestlaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/3776276280.pdfIn PDF document text
    • https://indiantalentjunction.com/milan/media/37468227893.pdfIn PDF document text
    • http://760_709737661.mildmedia-dev.eu/uploads/userfiles/files/buzuwudapazixa.pdfIn PDF document text
    • http://www.eflox.net/wp-content/plugins/formcraft/file-upload/server/content/files/1613b50cc6cb21---welise.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/LPIa9PGmDLg/uplcv?utm_term=early+stage+measles+symptoms+in+babiesPDF 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_off0000cb79.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB79 10832 bytes
SHA-256: cf169112dc24f4969ffe415af23d0961e6fa2143915074b84ba0b081ddd20d23
font_01_sfnt_off0000e43a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE43A 17640 bytes
SHA-256: 9a3b32f00337bd82757dc9310569a9585d2e58b885c92c326aaeb593d1f1c1c0
font_02_sfnt_off000111aa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111AA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1