Malicious PDF — malware analysis report

Static analysis result for SHA-256 5036b6d8352aa4f6…

MALICIOUS

PDF

76.7 KB Created: 2021-09-13 14:36:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 5732e46843cae469b68dab920c068c31 SHA-1: 2189526842a682d333c30eb0936843b327e576a0 SHA-256: 5036b6d8352aa4f60139834c205e9041a6670a7b998e3ddb0ba8c44989ef808c
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous external links, many pointing to other PDF files hosted on various domains. Several heuristics indicate this is a link farm, with some links pointing to compromised CMS uploads. The ML classifier strongly flagged this PDF as malicious. The primary attack pattern observed is the use of a link farm to direct users to potentially malicious content, likely as part of a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9908

Heuristics 5

  • 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://pistant.ru/uplcv?utm_term=hearts+card+game+io PDF link annotation
    • http://j-line.ca/fck_upload/file/tevuwufuriruv.pdfIn PDF document text
    • http://perfect-aerosol.eu/userfiles/file/nuxujun.pdfIn PDF document text
    • http://ntvietnga.com/upload/files/25596491459.pdfIn PDF document text
    • http://kiko168.com/UploadFile/file/20210908061313840.pdfIn PDF document text
    • http://rivebistro.net/ckfinder/userfiles/files/96734446472.pdfIn PDF document text
    • http://www.shipsupply.co.mz/wp-content/plugins/formcraft/file-upload/server/content/files/1613f211f29838---buvibumokowaremise.pdfIn PDF document text
    • http://texinpack.com/uploadfile/file///2021090716065147.pdfIn PDF document text
    • https://zapcdn.space/web/img/podborky/files/zatimetupunamuve.pdfIn PDF document text
    • https://tenshinorchids.com/FCKeditor_upload/file/xuxegizanorotirutepub.pdfIn PDF document text
    • http://miryangpension.com/FileData/ckfinder/files/20210913_E5074CD3FEE3A77C.pdfIn PDF document text
    • https://estidevelopers.com/wp-content/plugins/super-forms/uploads/php/files/cafac6daae8b4f5e41ca15eadbe0e3d4/7821673596.pdfIn PDF document text
    • http://domingo.hu/ckfinder/userfiles/files/90863186169.pdfIn PDF document text
    • http://xn--2e0b95unoa536adofm5h.com/userfiles/file/79078567717.pdfIn PDF document text
    • http://zenobiacultura.it/userfiles/file///83429490227.pdfIn PDF document text
    • http://oralrem.kz/ckfinder/userfiles/files/99556180264.pdfIn PDF document text
    • http://joshuadacosta.com/wp-content/plugins/formcraft/file-upload/server/content/files/16137fdcc4903f---37088460340.pdfIn PDF document text
    • https://suhrsmad.dk/wp-content/plugins/formcraft/file-upload/server/content/files/1613ce2a2a8dee---49991481649.pdfIn PDF document text
    • https://abhimaninteriors.com/ckfinder/userfiles/files/nelopozilezu.pdfIn PDF document text
    • http://abwcoliseum.com/uploads/files/lofujonawopux.pdfIn PDF document text
    • https://appchecar.com/ckfinder/userfiles/files/65365474470.pdfIn PDF document text
    • http://kennyre.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613bdae2b3460---32676168078.pdfIn PDF document text
    • https://maydongy.com/wp-content/plugins/super-forms/uploads/php/files/ed1mgmnsj8uj0hc6fq5jvdsgh7/69869342969.pdfIn PDF document text
    • https://nutrishop.in/ci/userfiles/files/70680176016.pdfIn PDF document text
    • http://dokturmice.com/ckfinder/userfiles/files/4590515413.pdfIn PDF document text
    • https://immo-cjeanpaul.lu/userfiles/files/52130777352.pdfIn PDF document text
    • http://alpes-maritimes.proximeo.com/ckfinder/userfiles/files/gijilu.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_off0000c889.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC889 10556 bytes
SHA-256: 55871eb8f0c5ecdf99f5d03b9b2017e99b98cc69fe9dcbf747550e7f246e7164
font_01_sfnt_off0000e067.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE067 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f879.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF879 17252 bytes
SHA-256: 458562826d24742c001fa094597fd98660d401f285f513666536da7fa43a0f9e

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