Malicious PDF — malware analysis report

Static analysis result for SHA-256 81f11f81a7a395e3…

MALICIOUS

PDF

79.7 KB Created: 2021-09-01 02:47:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: cf15933218684363b251a0692199c543 SHA-1: c3629b149b19dc34f4a504fdd5fafcccfdfd8f28 SHA-256: 81f11f81a7a395e3bd473250d3883e0fa4ee6a5372b878fee2476083872d12f8
156 Risk Score

Malware Insights

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

The PDF contains numerous links pointing to compromised WordPress sites, indicating a link farm designed to host malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or malware distribution. The document body was unreadable, but the heuristics clearly indicate the presence of a link farm on disposable hosting.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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://nuregio.de/wp-content/plugins/formcraft/file-upload/server/content/files/16096c6ef267d6---fitokiputagam.pdf In PDF document text
    • https://www.mclarenpress.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a6992209b36---zutawad.pdfIn PDF document text
    • https://www.ideaklinikbakirkoy.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606d8e0fa71cb---devafiwasowuwifeloji.pdfIn PDF document text
    • http://www.kmclogistics.com/wp-content/plugins/super-forms/uploads/php/files/9b2deb11a6d6f5b755b14743da511e0c/83637212652.pdfIn PDF document text
    • https://humantouchtranslations.com/wp-content/plugins/formcraft/file-upload/server/content/files/1/160aa9b625e55a---26519005347.pdfIn PDF document text
    • https://flylights.pl/wp-content/plugins/super-forms/uploads/php/files/lj93n627k2ltbpcsm1gpaodg46/56232522329.pdfIn PDF document text
    • http://thegioidahoacuong.com/uploads/image/files/sokovofofupir.pdfIn PDF document text
    • https://www.jemelectric.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a7e577c35cf---39351702694.pdfIn PDF document text
    • http://cnc-soustruzeni.cz/files/file/63079093846.pdfIn PDF document text
    • http://asbu.net/uploads/FCK_files/file/13860765888.pdfIn PDF document text
    • http://discarga.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a5c6f8edf89---xuwojuxezotubazevafeduk.pdfIn PDF document text
    • http://terapie-psi.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16117832253635---fakuludawi.pdfIn PDF document text
    • http://www.theflightfest.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609464ee062fd---43865685816.pdfIn PDF document text
    • http://www.onegelha.com/wp-content/plugins/super-forms/uploads/php/files/0e9ec1912a4b65f9b1069bac1ece9371/65680650916.pdfIn PDF document text
    • https://www.dentaltaxpros.com/wp-content/plugins/super-forms/uploads/php/files/a7265c32d9f35c910b99556f622a1d18/52507288932.pdfIn PDF document text
    • https://snabavto.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607f7c0e9d969---gogojali.pdfIn PDF document text
    • http://reiki-roots.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16070d2da375dc---56451079442.pdfIn PDF document text
    • http://sunnysolutions.it/uploads/assets/file/77533271579.pdfIn PDF document text
    • https://shrmivirtual.org/wp-content/plugins/super-forms/uploads/php/files/1c8d0ded02839443f435b89186e58844/26591344414.pdfIn PDF document text
    • https://jaunimodienos.lt/wp-content/plugins/super-forms/uploads/php/files/70uki0aguln8874d8ipmei00in/53851658594.pdfIn PDF document text
    • http://cbelmira.com/wp-content/plugins/super-forms/uploads/php/files/8087ba9fe01fbc8b5823732036153520/66776605300.pdfIn PDF document text
    • http://studiocommercialedelpiano.it/userfiles/files/88117516932.pdfIn PDF document text
    • http://tctrack.vn/images/newtech/files/21718402190.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=formula+to+find+total+surface+area+of+cylinderPDF 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_off0000d1aa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD1AA 10828 bytes
SHA-256: 611e9b88f67ef5b77a8da3e9f7fa6d433268e8cf2e16d81e042cee9bd134cdaf
font_01_sfnt_off0000eaa4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEAA4 17600 bytes
SHA-256: 3175373e6ad8c7d64924662ed2997f9c4c982dc536515a267026cd4fdbc59d5b
font_02_sfnt_off00011879.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11879 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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