Malicious PDF — malware analysis report

Static analysis result for SHA-256 b835b55d28c0ab13…

MALICIOUS

PDF

74.0 KB Created: 2021-06-12 04:47:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-11
MD5: cc19432a06f0caeced9505221a4d5214 SHA-1: ddb9ecdcd8a4af8ce50a13fc9d0382794bae1c5f SHA-256: b835b55d28c0ab13b294a97ad33cb2bcd2d69f18e5386307bef12dee6a45a532
156 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The document contains numerous external links, many pointing to compromised WordPress sites and disposable hosting, suggesting a link farm used for SEO poisoning to lure victims. The primary URL, 'https://inwebjor.ru/uplcv?utm_term=breathing+and+exchange+of+gases+neet+notes+pdf+free+download', is presented as a free download for study notes, a common phishing pretext. While no scripts were explicitly extracted, the PDF structure and numerous embedded URLs strongly suggest it's designed to redirect users to malicious content or download further payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://inwebjor.ru/uplcv?utm_term=breathing+and+exchange+of+gases+neet+notes+pdf+free+download PDF link annotation
    • http://rolmech-strzelno.pl/Upload/file/48265270332.pdfIn PDF document text
    • https://www.pietri-automobiles.com/wp-content/plugins/super-forms/uploads/php/files/lscte16c6ud6781tb79jmdtl0g/19680358459.pdfIn PDF document text
    • http://eszixv.hu/ckfinder/userfiles/files/jilugobisevawoxubulago.pdfIn PDF document text
    • https://voolabs.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f5d10f1e66---valoten.pdfIn PDF document text
    • https://www.saltriot.com/wp-content/plugins/super-forms/uploads/php/files/15385bb703ae230c056cae126335522c/bovakoxetexexulasutaxo.pdfIn PDF document text
    • http://eske.hu/wp-content/plugins/formcraft/file-upload/server/content/files/160c2ebe294fc0---nenevinafovufadepejitemu.pdfIn PDF document text
    • http://al-bandak.com/userfiles/file/pipetosaseromolifexof.pdfIn PDF document text
    • http://sam-global.info/files/file/67223226653.pdfIn PDF document text
    • http://hellnocancershow.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a751f4c72c3---vejofusazelu.pdfIn PDF document text
    • https://benqmusicworkshop.com/fupload/file/wotisofibivibirejopag.pdfIn PDF document text
    • http://webinside.pl/userfiles/file/57624514114.pdfIn PDF document text
    • https://agrotehholding.ru/wp-content/plugins/super-forms/uploads/php/files/471a5f6b941489509179e6834b216c2e/pajoj.pdfIn PDF document text
    • http://www.thebetterinsurance.com/wp-content/plugins/formcraft/file-upload/server/content/files/160825be34278c---79081411584.pdfIn PDF document text
    • http://constructionone.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16082ac95884af---24751894940.pdfIn PDF document text
    • https://sandalyecenneti.com/wp-content/plugins/super-forms/uploads/php/files/5i9kumtmi2cd40u3e8f4sfisrf/32232912868.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

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e1e5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE1E5 5628 bytes
SHA-256: ffe3ca923dafa59bbd7bc0ff0fba52e9575e772d30ec9e491336067d4ee4ea48
font_01_sfnt_off0000f522.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF522 11096 bytes
SHA-256: 0d5df62089ff2774df640aad65c3a374c11da6dc0dc483e63b1651b531a481f4