Malicious PDF — malware analysis report

Static analysis result for SHA-256 71b44ab7fb1053e9…

MALICIOUS

PDF

101.3 KB Created: 2021-09-06 11:06:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 9fd7261e0d56febba5a8320857df7f8c SHA-1: 8ef55847bb00d021803f8bc667d4f1f6869ee456 SHA-256: 71b44ab7fb1053e931dd98e17710d724699bff5b67ecbb4f810d7e1c66de4c0f
156 Risk Score

Malware Insights

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

The PDF contains numerous links, many pointing to compromised CMS upload directories, suggesting it's part of a phishing or malware distribution campaign. The ML classifier and ClamAV detection strongly indicate malicious intent. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, not containing user-readable content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9961

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://sipare.com.ar/wp-content/plugins/super-forms/uploads/php/files/9oblp4ih6mpbhhasstoeusjtqv/12835116636.pdf In PDF document text
    • http://www.pics4us.de/userfiles/file/50427953148.pdfIn PDF document text
    • https://amitadevnani.com/userfiles/file/bekepipodok.pdfIn PDF document text
    • http://computer-rudolstadt.de/upload/file/88061960410.pdfIn PDF document text
    • http://www.iso-clean.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1608ddfa792335---4486392789.pdfIn PDF document text
    • https://www.mozartcantat.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160bc9c58532cc---sofomoposajogo.pdfIn PDF document text
    • http://sklepjola.pl/userfiles/file/96230931846.pdfIn PDF document text
    • http://files.ibiza-ferien.de/file/80257446939.pdfIn PDF document text
    • http://gostium.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607fb1b509a65---51923933721.pdfIn PDF document text
    • https://delta-relay.be/userfiles/file/vavowipa.pdfIn PDF document text
    • https://soechi.id/userfiles/file/datige.pdfIn PDF document text
    • http://dentalclinicbangalore.com/uploads/foxera.pdfIn PDF document text
    • https://cowichanseniors.ca/userfiles/file/84513061911.pdfIn PDF document text
    • http://manavpublicschool.org/manav/userfiles/file/28813992012.pdfIn PDF document text
    • https://miamivanservice.net/wp-content/plugins/formcraft/file-upload/server/content/files/160bab58150114---71198755013.pdfIn PDF document text
    • http://www.cascinasorigherio.it/wp-content/plugins/formcraft/file-upload/server/content/files/161214c9130b61---gitosegokus.pdfIn PDF document text
    • http://gpszone.hu/upload/userfiles/file/91079298956.pdfIn PDF document text
    • http://beckydavidsonhomes.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d26d013c02b---65867020411.pdfIn PDF document text
    • http://cnhhgj.com/upfiles/userfiles/file/kalowudaporudutomepe.pdfIn PDF document text
    • http://tw-sincere.com/upfiles/editor/files/vifasoninitedowosedato.pdfIn PDF document text
    • http://associatedreclaimed.com/userfiles/files/gasarupabojonuzanujegu.pdfIn PDF document text
    • http://www.peplex.it/wp-content/plugins/formcraft/file-upload/server/content/files/160ed085d47215---19679246992.pdfIn PDF document text
    • https://espiber.cl/images/uploadedimages/file/kudibegozoro.pdfIn PDF document text
    • https://secolink.sk/userfiles/file/92634855903.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1KS0DP0cxss/uplcv?utm_term=corneal+ulcer+treatment+guidelines+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_off00012573.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12573 11092 bytes
SHA-256: 9e3a5fcf97394988e9d7aa84aa6602cf5a8e9c207ab3e4f2f1c9c72e4c5f4177
font_01_sfnt_off00013f19.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13F19 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001572b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1572B 18284 bytes
SHA-256: ef5b927381d3b6fcca92f0692405af0326b11f092b7539bca99232758d007bb1

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