Malicious PDF — malware analysis report

Static analysis result for SHA-256 7913f57459ceb554…

MALICIOUS

PDF

90.0 KB Created: 2021-09-02 10:16:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 4cfcbf4e2e9faa84b38796c8541d708f SHA-1: 48d1a8a2e22b0dd5c693fb9eb9ea4095ecba0a1c SHA-256: 7913f57459ceb5545486ed1e9ddc3e82ed5b67fc8f62bcfda5f3db83d4c94bb0
156 Risk Score

Malware Insights

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

The PDF contains a large number of embedded URLs, many of which point to external PDF files hosted on various domains. Several heuristics indicate this is a link farm, with some links pointing to compromised CMS upload storage. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or distributing further malware through these linked PDFs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

Heuristics 6

  • 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.
  • 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://zifu-tech.com/app/webroot/userfiles/files/nixonupo.pdf In PDF document text
    • https://regalcabs.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1607ba9c69c7b1---fetakukamusamimobugijoja.pdfIn PDF document text
    • http://www.heksan.com.pl/file/padimado.pdfIn PDF document text
    • https://bem-sa.com/img/file/dineriwul.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c0cb912be29---wijul.pdfIn PDF document text
    • https://bykevin.com/wp-content/plugins/super-forms/uploads/php/files/0bae2dda5c489aefb387698700e1a28c/94819591017.pdfIn PDF document text
    • http://www.startservis.sk/novy/ckfinder/userfiles/files/viwujunizopakivinu.pdfIn PDF document text
    • http://arohitourandtravels.com/userfiles/file/88961294047.pdfIn PDF document text
    • http://loveforlungs.com/clients/a/a9/a9a80f3a93b7553e0860ec1960497db0/File/gegukuwekesevesu.pdfIn PDF document text
    • https://actaviaserica.org/board/file/files/76309349886.pdfIn PDF document text
    • http://eko-inwest.eu/upload/file/kewakimazide.pdfIn PDF document text
    • http://sowa-architekci.pl/userfiles/files/41537566328.pdfIn PDF document text
    • https://alkalacarservice.com/public_html/userfiles/file/84165717784.pdfIn PDF document text
    • http://xn----itbbfrdrdbd4bgy6gi.xn--p1ai/webroot/files/files/94973250541.pdfIn PDF document text
    • http://www.majorisinvestimentos.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160c9c229775bd---febuwu.pdfIn PDF document text
    • https://didacostruzioni.it/userfiles/file/gomibura.pdfIn PDF document text
    • http://sostrevalli.it/userfiles/files/57234653816.pdfIn PDF document text
    • https://braindevelopmentmaps.org/userfiles/files/nonidigugizamakije.pdfIn PDF document text
    • http://duepassidalcentro.it/userfiles/files/51060229709.pdfIn PDF document text
    • http://thegibbsfamilyreunion.com/clients/d/d9/d929505c7faf6263097cc97620c39d65/File/ramirifidojosokidetuki.pdfIn PDF document text
    • http://liddellgaryfamily.com/clients/863293/File/jabuterap.pdfIn PDF document text
    • https://shared401k.com/wp-content/plugins/super-forms/uploads/php/files/379792c221f66864576957f200ba2ce0/pidijod.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=the+girl+with+the+dragon+tattoo+2005PDF 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_off0000f9c3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9C3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000111d5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111D5 18452 bytes
SHA-256: cdb4dea720fb5126ead29a434a07c5960e075bb860e7bd72a01aeaf5924ad08b
font_02_sfnt_off0001417f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1417F 10784 bytes
SHA-256: a7273920ae0fee52608513f48ddd679a5f722b88e4c9d1477609de9f27133a76

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