Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef6f3e73659367bc…

MALICIOUS

PDF

82.7 KB Created: 2021-09-03 14:18:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 26bd5dbd44b57fe576c3cfb4779b90ca SHA-1: 3574dad99518703d5f8df7fdb0765f3c2bfef5fe SHA-256: ef6f3e73659367bc2c3cd7ae7add8a2b883593595456cef8eccf6074bda84f1b
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous external URLs, many hosted on compromised or disposable domains, suggesting a phishing or link-farming scheme. The presence of PDF-specific heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' further supports this, indicating the PDF is used to redirect users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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=kanker+prostat+pdf PDF link annotation
    • http://redactron.com/userfiles/file/56764489770.pdfIn PDF document text
    • http://gocep.org/data/userfiles/files/88204090679.pdfIn PDF document text
    • https://www.rockandroll.blog.br/wp-content/plugins/super-forms/uploads/php/files/bf9qi7d8fni5ib164cneia2e44/gapumonodirumidala.pdfIn PDF document text
    • http://poslovniimenik.net/firme_data/files/vizorugiwupijokedofo.pdfIn PDF document text
    • http://woorymart.com/userData/board/file/soxives.pdfIn PDF document text
    • http://cedresarquitectura.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606ff8b790979---pomab.pdfIn PDF document text
    • http://limeitec.com/upfiles/editor/files/xekolafujivatojef.pdfIn PDF document text
    • http://acmemask.com/upfiles/editor/files/75640275477.pdfIn PDF document text
    • http://hotelbasantresidency.com/uploads/zulubu.pdfIn PDF document text
    • https://mystruggle.uk/indigo/ckfinder/userfiles/files/lafeverukatenagid.pdfIn PDF document text
    • https://www.phoenixdentalacademy.co.uk/wp-content/plugins/super-forms/uploads/php/files/21681f5e2bed2bafaf9a769a5b2f8a3e/61401574445.pdfIn PDF document text
    • http://wurbs-hanau.de/userfiles/file/fusuwazaluk.pdfIn PDF document text
    • http://consade.com/userfiles/file/90924775933.pdfIn PDF document text
    • http://www.cerathai.com/image/upload/File/sirupojodizudunagageviso.pdfIn PDF document text
    • http://jaatkinson.com/userimages/5687518643.pdfIn PDF document text
    • http://ausafe.net/images/art/files/36514131691.pdfIn PDF document text
    • http://modelkyujin.com/wp-content/plugins/formcraft/file-upload/server/content/files/16098a8cecf2a2---75838884641.pdfIn PDF document text
    • https://hobbes-group.com/upload/files/kerejavenerube.pdfIn PDF document text
    • http://erainbowrealty.com/userfiles/file/donuxidal.pdfIn PDF document text
    • https://baxsporthorses.nl/userfiles/file/95831600499.pdfIn PDF document text
    • https://thewaves.net/wp-content/plugins/super-forms/uploads/php/files/39ism39pdn0t11hio8hdgl1uvq/xumotipov.pdfIn PDF document text
    • http://www.x454.com/wp-content/plugins/super-forms/uploads/php/files/p1s34m50abrh138jllum57fma2/vapadalijesudupujixu.pdfIn PDF document text
    • http://theheavent.com/userfiles/files/49471144537.pdfIn PDF document text
    • https://www.rockandroll.blog.br/wp-content/plugins/super-forms/uploads/php/files/84kflbm8nqa2397hfqfit4h3tp/rukaxoxamadutalad.pdfIn PDF document text
    • http://work4shop.cz/userfiles/file/24120684246.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_off0000e254.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE254 16536 bytes
SHA-256: 8faf7a288229b5dbd77ec3276a5491484f52563ec8cf797c6e6a77c6aead9696
font_01_sfnt_off00010d39.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D39 10436 bytes
SHA-256: 7b80c1c3c9e5e5649b031b3e506cc3ad2d5cb71945f887981c7cb5ed14ab402f
font_02_sfnt_off0001250b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1250B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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