Malicious PDF — malware analysis report

Static analysis result for SHA-256 f31fd91ffe59c327…

MALICIOUS

PDF

70.7 KB Created: 2021-09-29 10:36:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 36304d8eb46d1dbfe6ab3ba71ee0c94b SHA-1: 1dab2662a051bf1350d15c673fb01d14bae27d5b SHA-256: f31fd91ffe59c327f0b0eeb252cd0a3967cc9a74dd7529c5a4177c94646a103b
96 Risk Score

Malware Insights

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

The PDF contains numerous links, many pointing to disposable hosting or compromised CMS upload directories, suggesting a link farm intended to distribute further malicious content. The ML classifier strongly indicated maliciousness. The presence of multiple PDF files in the URLs suggests the primary goal is to redirect users to download other malicious documents.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9849

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://cowik.pl/upload/62170354287.pdf In PDF document text
    • http://storemisr.com/uploads/files/79197335253.pdfIn PDF document text
    • http://psn-monolit.ru/img_file/files/93887841165.pdfIn PDF document text
    • http://griesvoegwerken.nl/UserFiles/file/dedomagibimumudibirevuro.pdfIn PDF document text
    • https://ckmusicdesign.nl/userfiles/file/81548510482.pdfIn PDF document text
    • https://www.pferde-fuer-unsere-kinder.de/wp-content/plugins/formcraft/file-upload/server/content/files/161521d1762044---94615239865.pdfIn PDF document text
    • http://ain.proximeo.com/ckfinder/userfiles/files/22874346307.pdfIn PDF document text
    • http://uniroll.pl/user_images/file/66060169873.pdfIn PDF document text
    • http://annabarons.com/files/files/fesojiseloteloxuju.pdfIn PDF document text
    • https://palcev.ru/userfiles/file/mubivadalabu.pdfIn PDF document text
    • http://polesprogettazioni.com/userfiles/files/pumorasovubige.pdfIn PDF document text
    • https://bike-accessories.supersites.gr/content/ckfinder/files/11972069121.pdfIn PDF document text
    • http://newshop.jp/archive/file/vokilidonemonatad.pdfIn PDF document text
    • http://dietaltop.com/userfiles/files/fapopezudo.pdfIn PDF document text
    • http://thailaundry.com/imgUpload/files/92953343984.pdfIn PDF document text
    • http://cageart.ca/wp-content/plugins/formcraft/file-upload/server/content/files/16136832a68942---71027290075.pdfIn PDF document text
    • http://suarezbeltran.com/aym_images/files/61021820069.pdfIn PDF document text
    • http://paglialonga.it/userfiles/files/vupigebew.pdfIn PDF document text
    • http://kemenyseprosiklos.hu/upload/file/lafigopotovaz.pdfIn PDF document text
    • https://retentionstudentexperience.com/wp-content/plugins/formcraft/file-upload/server/content/files/161479c09919a6---vupaveb.pdfIn PDF document text
    • https://rwd1.thadv.com/upload/files/xepegiroxorijov.pdfIn PDF document text
    • http://hotelpenza58.ru/ckfinder/userfiles/files/lonulavuroruwolekugede.pdfIn PDF document text
    • http://clearspace-design.com/CKEdit/upload/files/67714834388.pdfIn PDF document text
    • http://www.iycadana.org/wp-content/plugins/super-forms/uploads/php/files/nin818u088v7ooj2lv1vgr4u97/50135160282.pdfIn PDF document text
    • http://4226080.kad.tw/kads/ckfinder/userfiles/files/75211382803.pdfIn PDF document text
    • https://bleikss.com/userfiles/file/tibomimo.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/YTWXjIUwRh0/uplcv?utm_term=new+sports+games+for+androidPDF 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_off0000b0fd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB0FD 10856 bytes
SHA-256: 612ea682ea132d4def3a22bd7a98fc85061b76d641288b53231418940775ed1f
font_01_sfnt_off0000c9f2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC9F2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e204.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE204 16404 bytes
SHA-256: 4fa408f74d97cc774639d4bee4c961543852d0ae2595abc9834aaad12fb736c7