Malicious PDF — malware analysis report

Static analysis result for SHA-256 6bdda1ccd41e082e…

MALICIOUS

PDF

96.6 KB Created: 2021-08-11 12:54:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: e78d2f87e7a591b28f8b9cff1069b94d SHA-1: c39f16fcf05ab602ee81ec57593a8b4a0b1ea38f SHA-256: 6bdda1ccd41e082ef268b4d72125737e56310463c8670f6fd99ee83ab1b5dfa2
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 User Execution: Malicious File

The PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with many embedded URLs pointing to compromised WordPress upload directories and other potentially untrusted domains. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for human readability but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://coolingrealestate.com/your-home-cleaner/FCKuploads/file/95475758429.pdf In PDF document text
    • http://www.viksexteriors.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e57f26b57bd---nitibapegobinokokefum.pdfIn PDF document text
    • http://www.klimavill.com//data/editorfile/31075644648.pdfIn PDF document text
    • http://www.barankayalar.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/160b4be6ec8e6c---legafelozoxuzoxarapididin.pdfIn PDF document text
    • https://cortemadera.com/wysiwygfiles/file/16654352755.pdfIn PDF document text
    • https://nevisnews.com/userfiles/kawepipudakoguragujaki.pdfIn PDF document text
    • http://sibmetiz.ru/upload_picture/63258532058.pdfIn PDF document text
    • http://sapaelitehotel.com/webroot/img/files/faviwamu.pdfIn PDF document text
    • https://saraelv.no/wp-content/plugins/formcraft/file-upload/server/content/files/160d6cc7c0c249---53505974520.pdfIn PDF document text
    • https://contact-house.com/fckeditor/upload/file/61679891839.pdfIn PDF document text
    • https://kfz-gutachter-oliver-schiller.de/wp-content/plugins/formcraft/file-upload/server/content/files/160bbaa5eccda8---34421850257.pdfIn PDF document text
    • http://eltonltd.ru/sites/default/files/uploads/xijovudidetunutafa.pdfIn PDF document text
    • http://vivaibonomo.it/userfiles/files/81441789090.pdfIn PDF document text
    • http://sage-chem.com/image/files/20210613_001937.pdfIn PDF document text
    • https://www.physioaktivkramer.de/wp-content/plugins/formcraft/file-upload/server/content/files/160ba4d6e73ec8---77213684164.pdfIn PDF document text
    • https://medgal.pl/admin/ckfinder/userfiles/files/28218511600.pdfIn PDF document text
    • https://esteticarcare.com/wp-content/plugins/super-forms/uploads/php/files/32e0fa3c9f7e12c4e67f7ab4af54aa5c/73239911093.pdfIn PDF document text
    • http://www.sealjet.mn/pictures/files/devadizobekufetixi.pdfIn PDF document text
    • https://majubesar.info/contents//files/11420080742.pdfIn PDF document text
    • http://libertyquad72.fr/userfiles/file/64554504873.pdfIn PDF document text
    • http://clinicaveterinariamontecchia.com/userfiles/files/62576227895.pdfIn PDF document text
    • https://www.18fire.com/wp-content/plugins/super-forms/uploads/php/files/9eb8d21598e9fae15fa1f99c51ec77aa/lirupu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/3vuEKuznOb8/uplcv?utm_term=navy+seal+training+guide+mental+toughness+pdfPDF 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_off000112f6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x112F6 11200 bytes
SHA-256: d80c72970fd2c09c7b0a9468bf1d812d693e0cdb6b388e6ae202aa2b2214a541
font_01_sfnt_off00012cd1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12CD1 17564 bytes
SHA-256: 8aa23b37da337d11aaba110d0e6378cabbf265888ce3a59eb24850637901fbb9
font_02_sfnt_off00015abc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15ABC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1