Malicious PDF — malware analysis report

Static analysis result for SHA-256 c81bb1e04a30fe57…

MALICIOUS

PDF

75.4 KB Created: 2021-09-07 19:29:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 709668cba5dfe86626ee8b061ec17100 SHA-1: 92df6e7b841a71fecd61b0e5adc4bc65a5948b54 SHA-256: c81bb1e04a30fe57b7150ee0760c61518e90bb82090c419aa5a304c1846c5940
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many pointing to compromised CMS upload directories, suggesting a link farm designed to redirect users to malicious content. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. Although no scripts were explicitly extracted, the nature of the embedded URLs and the heuristic firings suggest the PDF is intended to exploit user interaction to navigate to potentially harmful sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9840

Heuristics 6

  • 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 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://wastran.ru/uplcv?utm_term=subitizing+worksheets+free PDF link annotation
    • https://santevita-bg.com/ckfinder/userfiles/files/91327060704.pdfIn PDF document text
    • https://arizonalightingsales.com/wp-content/plugins/super-forms/uploads/php/files/753d1152cb12243b7b0ee7184a9de268/78768934087.pdfIn PDF document text
    • http://tantex.org/tantex/tantexuserfiles/file/famabunusakiduwavol.pdfIn PDF document text
    • http://kondicionery-vidnoe.ru/upload_picture/file/sufewomijit.pdfIn PDF document text
    • https://biorenta.lt/ckfinder/userfiles/files/21263864161.pdfIn PDF document text
    • https://hsegroup.ru/wp-content/plugins/super-forms/uploads/php/files/mf95i6ajj7jvrh122e1gt04g70/tidajubimivikonofonogage.pdfIn PDF document text
    • http://sity-luxe.ru/userfiles/file/8823078222.pdfIn PDF document text
    • http://www.scmphotography.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16082232912258---sokejajodi.pdfIn PDF document text
    • http://logisticsnetworks.net/ckfinder/userfiles/files/jumuvuwemokiwatorafeve.pdfIn PDF document text
    • http://agenziadiviaggiocagliari.it/file/97581680440.pdfIn PDF document text
    • http://builderall.info/userfiles/file/10315014039.pdfIn PDF document text
    • https://www.gryf-wet.pl/ckfinder/userfiles/files/xavogipugivesoxed.pdfIn PDF document text
    • http://cogersquest.com/clients/f/f6/f6194b381802d71b6842d6160e8859b1/File/taruxuwulusekipove.pdfIn PDF document text
    • http://beijinghuojia.cn/userfiles/file/bugame.pdfIn PDF document text
    • http://www.dadosefatos.net.br/wp-content/plugins/formcraft/file-upload/server/content/files/1606f1720ae383---sabazikifavuvamuxilap.pdfIn PDF document text
    • https://vv-alc.nl/uploads/files/lujem.pdfIn PDF document text
    • https://portsidestrategies.com/wp-content/plugins/super-forms/uploads/php/files/f5747af31b6cfa95413ad5612e72b15a/suxipizumovirulabogir.pdfIn PDF document text
    • http://dobre-jaja.com/Upload/file/11118362015.pdfIn PDF document text
    • http://speckrepeg.by/UserFiles/files/wuleroveruguxikajowebop.pdfIn PDF document text
    • https://www.popcaffe.it/wp-content/plugins/super-forms/uploads/php/files/cfab5d176c265aecf95e4ba8f2fb632d/laxuzefodurufemix.pdfIn PDF document text
    • http://lhs60to70.com/clients/3/32/32806278e47d7e4d905c37b1d6ebf04a/File/tugoxeduduripomobewewo.pdfIn PDF document text
    • http://philippinesroadshow.com/wp-content/plugins/super-forms/uploads/php/files/044a39854015f9bad54994e41f11ddff/ribigufifowexabi.pdfIn PDF document text
    • http://planet-for-events.de/userfiles/file/33665847539.pdfIn PDF document text
    • http://dfh-consulting.com/userfiles/file/jenixelaga.pdfIn PDF document text
    • http://jlm-kg.com/uploads/file/fupenegapek.pdfIn PDF document text
    • http://csc0351.com/userfiles/file/20210830130233_89z1cx.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_off0000c1e8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC1E8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d9fa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9FA 17564 bytes
SHA-256: b70ca20041af63c7d0c1a9bbed02a814766a0fb3d42765c10f3cce81bc2086ff
font_02_sfnt_off00010701.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10701 10840 bytes
SHA-256: 67bb59bb45b86a76a8d59f0eb3becede53920e460ac60e9509a6af86a536b140