Malicious PDF — malware analysis report

Static analysis result for SHA-256 8b3ceac5307cb40f…

MALICIOUS

PDF

83.5 KB Created: 2021-09-10 01:04:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 126c2e3c3313262940ea26ed9a889fd8 SHA-1: 13804609924ce4eaa341ca6541d726fe7358aced SHA-256: 8b3ceac5307cb40f9109b4ee69ec3e2b3f30d6af6ef2a615e80f56ff3c3c0589
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains numerous embedded URLs, many of which point to compromised CMS upload directories or disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution via these links. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host the malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

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 http://vetcarefoundation.org/userfiles/file/suwokijugevoruzilinawo.pdf In PDF document text
    • http://www.eflox.net/wp-content/plugins/formcraft/file-upload/server/content/files/161389cb2ca130---62197168512.pdfIn PDF document text
    • http://smartdeal.pl/files/upload/files/12721509387.pdfIn PDF document text
    • https://minhkygroup.com/luutru/files/jitixufovivaligis.pdfIn PDF document text
    • https://indirimlipin.com/calisma2/files/uploads/81133757447.pdfIn PDF document text
    • https://medgal.pl/admin/ckfinder/userfiles/files/marodojigozema.pdfIn PDF document text
    • https://rosebankprimary.co.za/inc/ckfinder/userfiles/files/dewoxapujixapixat.pdfIn PDF document text
    • http://csp.hu/editor_up/71496508511.pdfIn PDF document text
    • https://joefairless.com/wp-content/plugins/super-forms/uploads/php/files/45670dfa2bfac20b27a308d1679ee363/mofipovikudululufo.pdfIn PDF document text
    • https://www.chauffeur-prive-nice.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1613565a18daa1---98713260623.pdfIn PDF document text
    • http://ahknchem.com/upload/files/91375907863.pdfIn PDF document text
    • http://generaltubi.com/container/ckfiles/files/mujigik.pdfIn PDF document text
    • http://lumieretvie.com/userfiles/file/92906359130.pdfIn PDF document text
    • https://pierreseche.fr/userfiles/file/7763268663.pdfIn PDF document text
    • https://stgeorgedentalcare.in/ckfinder/userfiles/files/12055369387.pdfIn PDF document text
    • http://kondicionery-himki.ru/upload_picture/file/betuvumajebibesovaxumek.pdfIn PDF document text
    • http://t-eamplus.de/web/editor/files/guzebolito.pdfIn PDF document text
    • http://www.holzbau-hoelzl.at/wp-content/plugins/formcraft/file-upload/server/content/files/161350453ec912---77986486554.pdfIn PDF document text
    • https://highrise.pl/file/bikigiwok.pdfIn PDF document text
    • https://ventana-sur.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613829b881eba.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/DOqCt-cVA4I/uplcv?utm_term=chicken+gun+gamesPDF 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_off0000e23b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE23B 10536 bytes
SHA-256: 24a84d16e26650f26a5eb852e1f88b9665ecb11294b8a8ea2f19754893873fb7
font_01_sfnt_off0000fa10.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA10 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011222.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11222 18092 bytes
SHA-256: 450e1c9a080d88a42bc21b160f1469d2a8b5a80aa246f59b7b77adae461ef9f5