Malicious PDF — malware analysis report

Static analysis result for SHA-256 681e38537aa37a8b…

MALICIOUS

PDF

81.5 KB Created: 2021-09-03 01:03:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: b442b9377722e6aae76058250c5a76d5 SHA-1: c5542c02394ee9a5532174c211aa52695d9099df SHA-256: 681e38537aa37a8b8e1c4b2548bb94638fd17584df405eab3be8540bbca55c4f
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised or disposable domains, indicating a link farm designed to manipulate search engine results or distribute malicious content. The ClamAV detection and ML classifier strongly suggest malicious intent, likely involving exploitation of PDF vulnerabilities to redirect users to harmful sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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 http://rebornfair.com/FileData/ckfinder/files/20210804_86AFE38329E64661.pdf In PDF document text
    • https://www.superioreagle.com/wp-content/plugins/formcraft/file-upload/server/content/files/160aa5053ee7c8---kofotuj.pdfIn PDF document text
    • http://simkoongschool.com/uploads/editer/files/senif.pdfIn PDF document text
    • http://gld-lining.com/user_img/files/pidalekutaxofomarovegiru.pdfIn PDF document text
    • http://abwgulfport.com/uploads/files/rupuxikaputap.pdfIn PDF document text
    • http://www.southforconstruction.com/frontend/web/ckfinder/userfiles/files/52542971796.pdfIn PDF document text
    • http://bearings-home.com/userfiles/file/kudovuwobuperid.pdfIn PDF document text
    • http://odnoklassniki-files.ru/images/uploads/files/7364770136.pdfIn PDF document text
    • http://sosnovgeo.ru/userfiles/file/88412232503.pdfIn PDF document text
    • http://bdpq.hungminhits.com/files/uploaded/files/zesazigosinad.pdfIn PDF document text
    • http://hchs1972.com/clients/2/2c/2cb73362227bcfbd3ed6ae01b5b3dc46/File/muxuzoxanogewowewawam.pdfIn PDF document text
    • http://ideviceplus.nl/app/webroot/files/userfiles/files/11527558101.pdfIn PDF document text
    • http://king-tableware.com/uploads/files/202108272146147461.pdfIn PDF document text
    • http://patriabrno.cz/userfiles/files/89829900491.pdfIn PDF document text
    • http://mvdeastudio.it/userfiles/files/ritaranaxujar.pdfIn PDF document text
    • https://barcelonamedicalcenter.com/files/galeria/files/bonamijulefegimaretufog.pdfIn PDF document text
    • http://amblesidewindermere.ca/fckuploads/images/file/21142472111.pdfIn PDF document text
    • https://spaslask.pl/wp-content/plugins/super-forms/uploads/php/files/2eokud0ahvq9viav1tb30hm0eo/roluwunug.pdfIn PDF document text
    • https://www.corridar.com/wp-content/plugins/super-forms/uploads/php/files/2vsnv5vcj6jfvnol0thq4rh631/senuj.pdfIn PDF document text
    • https://cochleartudaskozpont.hufiles/96906060257.pdfIn PDF document text
    • http://dfh-consulting.com/userfiles/file/82851780720.pdfIn PDF document text
    • https://asigurareingermania.ro/wp-content/plugins/super-forms/uploads/php/files/gvdktesmqj06hp7hjd778djn2n/noxavasabo.pdfIn PDF document text
    • https://www.lesson-online.org/wp-content/plugins/super-forms/uploads/php/files/ffvv677hpi2n73rfcqpc9f2051/44667933042.pdfIn PDF document text
    • http://www.colegiometa.net/home/wp-content/plugins/formcraft/file-upload/server/content/files/160756525b7e09---xiwanokezoxamusijed.pdfIn PDF document text
    • https://12tiga.com/contents//files/ribubowotokizew.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1KS0DP0cxss/uplcv?utm_term=housing+allowance+form+pdfPDF 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_off0000dacb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDACB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f2e2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2E2 11040 bytes
SHA-256: d01a92aa558daf7d603b5bda76849253bb71032094a198b6e4fed2562dcc7849
font_02_sfnt_off00010c5d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C5D 16724 bytes
SHA-256: 10f75d93c2138f082b69e529744da89ebe8f7325101bdd3b1775cf4dbfe740c1

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