Malicious PDF — malware analysis report

Static analysis result for SHA-256 042638de1d458f3a…

MALICIOUS

PDF

84.6 KB Created: 2021-09-06 22:16:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 57273f7b5df323ed2f1f019e257a815a SHA-1: fb315290aba1174224aa2bfb235d1c05311488c7 SHA-256: 042638de1d458f3a1c1c2244a147277dbdde3c9b82033f95b85017fc4274fa45
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ClamAV and an ML classifier, with heuristics indicating embedded JavaScript and a link farm pointing to potentially compromised CMS upload directories. The PDF document body is heavily obfuscated, but the presence of JavaScript and numerous external URIs suggests an attempt to redirect the user to malicious content, likely for phishing or further malware delivery. The link farm structure and use of compromised WordPress sites are common tactics for evading detection and distributing malicious payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://www.varishastalari.com/wp-content/plugins/formcraft/file-upload/server/content/files/16078deb881e0a---babuvugamafolano.pdf In PDF document text
    • https://cor.org.ar/wp-content/plugins/super-forms/uploads/php/files/lqqd1a03qkma59io5jeoot0g05/98512341469.pdfIn PDF document text
    • http://archgeo-leszno.pl/uploads/userfiles/files/zenekugawibexizasixone.pdfIn PDF document text
    • http://www.brennholz-heinlein.de/wp-content/plugins/formcraft/file-upload/server/content/files/1606f43ad15de9---kodevogasafem.pdfIn PDF document text
    • http://www.fsnn.se/wp-content/plugins/formcraft/file-upload/server/content/files/160ad147510b2e---87052063628.pdfIn PDF document text
    • http://indiebookoftheday.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607005db140a4---95847700062.pdfIn PDF document text
    • http://softtox.com/new/userfiles/file/vuzosufaveba.pdfIn PDF document text
    • http://chinhsuasolieu.com/media/files/50248829384.pdfIn PDF document text
    • https://gulceoyunlar.com/calisma2/files/uploads/nuzivagaruzaw.pdfIn PDF document text
    • http://classiccar-jp.com/js/upload/files/22731970981.pdfIn PDF document text
    • https://tavio.ru/files/file/xafopuruwaxinizimopu.pdfIn PDF document text
    • https://berbagiangka.com/contents//files/xefimudamexegadanifavidi.pdfIn PDF document text
    • http://ovartec.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607d206f27172---36681341661.pdfIn PDF document text
    • http://plenaadoracao.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160766365de963---65823990048.pdfIn PDF document text
    • http://aceonlinementors.com/userfiles/file/16617246582.pdfIn PDF document text
    • https://maydongy.com/wp-content/plugins/super-forms/uploads/php/files/66uk02a0iq6qdgkgjhdbu3oq39/bonedini.pdfIn PDF document text
    • https://seataclightingalaska.com/wp-content/plugins/super-forms/uploads/php/files/572556ace8b1eda52e8864a6650f182a/73006297844.pdfIn PDF document text
    • https://moniimpex.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ba4d71d764d---84327647222.pdfIn PDF document text
    • https://40parables.com/wp-content/plugins/super-forms/uploads/php/files/e0df433a2843d800d3cd1e50f6ef87bd/zolotubakorife.pdfIn PDF document text
    • http://go-forum.cn/upload/files/vutaketejux.pdfIn PDF document text
    • http://vipavtoufa.ru/wp-content/plugins/super-forms/uploads/php/files/1263f6a84358599998345c355475b20a/48985038768.pdfIn PDF document text
    • http://ziconiavip.com/uploadfck/file/duvazebixir.pdfIn PDF document text
    • https://barcelonacentremedic.cat/files/galeria/files/wisoseziropupe.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/zMnd8XtcwSM/uplcv?utm_term=agentes+leudantes+en+panaderia+pdfPDF link annotation
    • https://sharpspringwww.kinsta.cloud/wp-content/plugins/super-forms/uploads/php/files/f0604ec445bb948e8685b7ac75343fd9/gozagebigujizepesud.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_off0000e23f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE23F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fa51.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA51 19524 bytes
SHA-256: 0af8cadb5e2eaec9d5e1113f5d80b41f281c17f2ce7f51a732d870406099a36c
font_02_sfnt_off00012a7e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12A7E 10636 bytes
SHA-256: 9f6f7050f6e899b5455bcb9c5b200d8d177e5a62cc76f3f15f3b59fcfcadb7bf

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