Malicious PDF — malware analysis report

Static analysis result for SHA-256 10bf38603de1149a…

MALICIOUS

PDF

91.8 KB Created: 2021-07-09 17:43:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: 4bd0fd9e812b475d743e921ef795e102 SHA-1: e9a7ed91f99c6f985a16a8db557124f472a83f47 SHA-256: 10bf38603de1149a05241d9deaff76aa329c7737b60eb0e59a771bba517304a4
104 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs pointing to compromised WordPress sites, indicating it functions as a link farm. The ML classifier strongly flagged this PDF as malicious, and heuristics confirm it's a link farm on disposable hosting. The primary attack pattern involves directing users to these external, potentially malicious, sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

Heuristics 6

  • 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.
  • Urgency / deadline lure low SE_URGENCY_LURE
    Document contains urgency or deadline language ('account will be terminated', 'action required within 24 hours', etc.) — useful context, but low-signal without other findings
  • 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://queure.ru/uplcv?utm_term=why+are+you+here+answer PDF link annotation
    • https://mission4recruitment.com/wp-content/plugins/formcraft/file-upload/server/content/files/16072ac76e934f---28347773504.pdfIn PDF document text
    • https://www.18fire.com/wp-content/plugins/super-forms/uploads/php/files/5e3903c69377018f6e01cf2af0bac475/34048702680.pdfIn PDF document text
    • https://vizzzio.ru/wp-content/plugins/super-forms/uploads/php/files/3b3afc23111e2ae81d0bdb256d326886/96462342636.pdfIn PDF document text
    • https://parklanehotel.asia/userfiles/file/13142342897.pdfIn PDF document text
    • https://bellevuecommunityfoodbank.org/wp-content/plugins/super-forms/uploads/php/files/72d490a88cd85a9294fe2f2587c4ec93/14696452394.pdfIn PDF document text
    • https://bouwservicewinthagen.nl/userfiles/image/file/89688565050.pdfIn PDF document text
    • https://lakeshoresmilesdentistry.com/wp-content/plugins/super-forms/uploads/php/files/7vrrrrsv0ag0h5anvh11hg5bm7/tagakidufekabox.pdfIn PDF document text
    • http://kasintorn.com/images/upload/files/sejimiregiparinuduwera.pdfIn PDF document text
    • https://gift-edu.ru/wp-content/plugins/super-forms/uploads/php/files/1363139c2a4b833607355cc67c9403b6/tarisimajeduj.pdfIn PDF document text
    • https://elitstroycraft.ru/source/file/77742354347.pdfIn PDF document text
    • http://montri-inspection.com/naichabub.co.th/images/upload/userfiles/files/belibibalidofejokapuwiwos.pdfIn PDF document text
    • https://tepihtrava.rs//files/doxavotifuwobe.pdfIn PDF document text
    • http://mebell-city.ru/ckfinder/userfiles/files/68751698871.pdfIn PDF document text
    • https://barcelonacentromedico.es/files/galeria/files/41196567425.pdfIn PDF document text
    • http://kubak-ubezpieczenia.pl/userfiles/file/21453195858.pdfIn PDF document text
    • http://soflocops.net/clients/81266/File/8544123709.pdfIn PDF document text
    • http://www.argentum.com/wp-content/plugins/super-forms/uploads/php/files/cdpsrcdie0a6pk5fi9op8b0ct4/12870407038.pdfIn PDF document text
    • http://immobilieninvestors.eu/userfiles/file/tofov.pdfIn PDF document text
    • http://mirai-kankyo.com/userfiles/files/43082966746.pdfIn PDF document text
    • http://www.marcelasemper.com/wp-content/plugins/formcraft/file-upload/server/content/files/16099eb2b63e7a---27420953064.pdfIn PDF document text
    • http://bitite.lv/media/txt/122/file/linejuv.pdfIn PDF document text
    • https://braviengenharia.com.br/wp-content/plugins/super-forms/uploads/php/files/a20ss6gsqmpkmsiq10e57mb86v/wufojowesu.pdfIn PDF document text
    • http://www.brennholz-heinlein.de/wp-content/plugins/formcraft/file-upload/server/content/files/160e3f6d59a100---todogufa.pdfIn PDF document text
    • http://worthingtonpark101.com/userimages/zuzulazivuxejok.pdfIn PDF document text
    • https://www.kunapak.com/wp-content/plugins/super-forms/uploads/php/files/qbbkd2hoaa54fajgf8gcokekll/30013496939.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_off000102f1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x102F1 10260 bytes
SHA-256: 14c2c17ae5098d403eee3f868c936364ff08729a64bad4b9cff43ff10cfa4c4e
font_01_sfnt_off00011a0a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11A0A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001321c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1321C 17676 bytes
SHA-256: 08fa88f9264b73624ac27427a1ffb88326bc18b9d8971a868b2cb97f9239df71