Malicious PDF — malware analysis report

Static analysis result for SHA-256 8d8f3961dd9723d2…

MALICIOUS

PDF

88.2 KB Created: 2021-09-02 08:06:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 6eabbbed733b0d85c073581500ff0005 SHA-1: 70392be7ee40811586ce5bf50733a30572d57561 SHA-256: 8d8f3961dd9723d21799c66496cbaeb4ad23bffc0871eaf9abc0439bb94a3b45
156 Risk Score

Malware Insights

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

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It functions as a link farm, with numerous URLs pointing to external sites, many hosted on compromised WordPress installations. The presence of multiple 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' heuristics strongly suggests the document's purpose is to distribute malicious content or phish users via these external links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9912

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://chcial.ru/uplcv?utm_term=sonic+heroes+ps3+download PDF link annotation
    • https://egyiksem.hu/uploads/file/32673110887.pdfIn PDF document text
    • http://sreema.org/FCKeditor/file/29667879804.pdfIn PDF document text
    • https://sharidendesignasphalt.com/wp-content/plugins/super-forms/uploads/php/files/c5cea4f9a1758cc6634e8dd61f356d44/72311348135.pdfIn PDF document text
    • http://ricarda-allegra.de/userfiles/file/48644298439.pdfIn PDF document text
    • https://schreinerheusi.de/wp-content/plugins/formcraft/file-upload/server/content/files/1608d53afeda90---35341148756.pdfIn PDF document text
    • http://myucmas.com/userfiles/file/84336541759.pdfIn PDF document text
    • https://ltssinternational.com/res/wysiwyg/file/pujarunudite.pdfIn PDF document text
    • http://mientaytourist.com/uploads/files/pudiwuru.pdfIn PDF document text
    • http://fuga-hotel.com/CKEdit/upload/files/41737771890.pdfIn PDF document text
    • http://www.ruben.pl/ckfinder/userfiles/files/tajuteborimosug.pdfIn PDF document text
    • https://pmcp-avac.com/files/upload-ckfinder/files/senonewebimib.pdfIn PDF document text
    • http://namthangbasaltstone.com/uploads/image/files/57246339825.pdfIn PDF document text
    • http://nnk.gr/wp-content/plugins/formcraft/file-upload/server/content/files/160abd5e006bad---67145062169.pdfIn PDF document text
    • http://inica.org/files/file///biwinudopedelawakez.pdfIn PDF document text
    • https://panegovernance.com/ourprojects/chowki/UserFiles/file/xozupibureravuropajir.pdfIn PDF document text
    • http://portaldo.eu/contenuti/upload/file/97375877293.pdfIn PDF document text
    • https://xn--mietkndigungsrecht-best-gpc.de/userfiles/file/31145625155.pdfIn PDF document text
    • https://amenajarisiconstructii.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160782bb43affb---wiminoretusat.pdfIn PDF document text
    • http://svenstavik.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b91c307ca41---mugorenegemetabirume.pdfIn PDF document text
    • http://victorylimo1.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a67f42036de---65355320322.pdfIn PDF document text
    • http://gsxr.hu/userfiles/file/vadixibowivusomolow.pdfIn PDF document text
    • https://www.sabiamente.es/wp-content/plugins/formcraft/file-upload/server/content/files/1607f0a6271c8f---26447475026.pdfIn PDF document text
    • https://lemarko.com/userfiles/file/safojid.pdfIn PDF document text
    • https://magerp.org/upload/files/6018153807.pdfIn PDF document text
    • http://nhasachconggiao.com/luutru/files/40561596569.pdfIn PDF document text
    • http://www.kidnuri.com/wp-content/plugins/formcraft/file-upload/server/content/files/160901a5e917bb---fuxobuvumodixepufekigogox.pdfIn PDF document text
    • https://chrmglobal.com/userfiles/file/44272643356.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_off0000f076.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF076 10844 bytes
SHA-256: 8adc1c173091385e9d20719a8f08357bb267f5f7fa8c4f4a8a5ce88981f36c63
font_01_sfnt_off00010972.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10972 18660 bytes
SHA-256: 557c9cbb82c3c8fa8ef759e8bf68cf2d022c06e3b4848ddcf2f3aed73b284862
font_02_sfnt_off00013a18.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13A18 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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