Malicious PDF — malware analysis report

Static analysis result for SHA-256 9635407941a85311…

MALICIOUS

PDF

76.7 KB Created: 2021-06-25 23:25:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-25
MD5: 219455a724879459f74a52c735b994e5 SHA-1: 3c887c735830d77620c5ccf5e5ec359debffc375 SHA-256: 9635407941a853115221fc7cbec5605a66efd722d8cd0bdc599c73b188002b3f
156 Risk Score

Malware Insights

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

The PDF was flagged by multiple heuristics as a link farm, with many URLs pointing to compromised CMS upload directories and disposable hosting. The ML classifier and ClamAV also identified it as malicious, specifically as a phishing trojan. The document body is heavily obfuscated and unreadable, suggesting it's not intended for human consumption but rather to host these malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

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 http://boekenwinkelindex.nl/images/uploads/fuvunuzuj.pdf In PDF document text
    • http://intechsol.kz/wp-content/plugins/formcraft/file-upload/server/content/files/160a3e0c4b48fa---6570456769.pdfIn PDF document text
    • http://www.misshandicap.ch/wp-content/plugins/formcraft/file-upload/server/content/files/160b0626f1acdb---61309616120.pdfIn PDF document text
    • https://angelsstaff.com/uploads/file/mifojibedadajubilasu.pdfIn PDF document text
    • https://livingcircles.ch/wp-content/plugins/formcraft/file-upload/server/content/files/16099bb2a0b574---16555051647.pdfIn PDF document text
    • http://thunderstar.cn/userfiles/file/20210512065411925458330.pdfIn PDF document text
    • http://le-lemniscus-incandescent.fr/ckeditor/upload/files/47317796658.pdfIn PDF document text
    • http://veterina-hrib.cz/user-uploads/files/tiwepetu.pdfIn PDF document text
    • https://autosaloncenter.com/uploads/file/rurujoreve.pdfIn PDF document text
    • http://poltinik.ru/userfiles/file/60695941128.pdfIn PDF document text
    • http://www.oschouston.com/osc/wp-content/plugins/formcraft/file-upload/server/content/files/1606ca42b0bdc4---21591388170.pdfIn PDF document text
    • http://flygarfield.net/userfiles/file/12300367955.pdfIn PDF document text
    • http://countrysquirefoods.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606c8e73251d1---gekutape.pdfIn PDF document text
    • https://www.financedeclined.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160865c9eb2f44---baviraboriwofi.pdfIn PDF document text
    • http://hungbuloon.com/media/ftp/file/serebonipaxemopajozi.pdfIn PDF document text
    • http://abc-tel.ru/data/File/jifovawiwawime.pdfIn PDF document text
    • https://rittenhousesmiles.com/wp-content/plugins/super-forms/uploads/php/files/79807496aeedb8d2b1d0f31c8d915663/nituninedefajovidodopuw.pdfIn PDF document text
    • https://readxyz.org/wp-content/plugins/super-forms/uploads/php/files/fdacc439b67da64c34274ac1b3dda742/lever.pdfIn PDF document text
    • https://gaseg.com/wp-content/plugins/super-forms/uploads/php/files/8jq3k43qco5hptns9eprfs64t7/sidiridabiziku.pdfIn PDF document text
    • https://janeunchained.com/wp-content/plugins/super-forms/uploads/php/files/eimr6t0o1o2prk2pk63p8uhp1a/xawiradifudavidafag.pdfIn PDF document text
    • https://hcs1000.org/wp-content/plugins/super-forms/uploads/php/files/ea3a2629159973c3c2d9278f2fbba8b9/mitimun.pdfIn PDF document text
    • http://www.nanodrywash.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c2e7ec0790a---64732785230.pdfIn PDF document text
    • https://maxflowfans.com/userfiles/file/pajoleluvefakikulodija.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/fzgW7-mxBc0/uplcv?utm_term=hob+kitchen+meaningPDF 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_off0000cb76.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB76 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e38d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE38D 10584 bytes
SHA-256: 6954c1c9c351dfa6a740ed8f63087e2799faa3b9d957af4e569484cf0c3b9550
font_02_sfnt_off0000fb7d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB7D 16392 bytes
SHA-256: eca352691cc4859f79b0516f3850f265248e3b434b94b50b8720072d7e9b4785

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