Malicious PDF — malware analysis report

Static analysis result for SHA-256 e28c5bd3da591dc9…

MALICIOUS

PDF

68.7 KB Created: 2021-09-26 05:58:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: ccdd26efd4b683946f0f107c23dcaee0 SHA-1: abc90c2ee89144e34ee4eaaa6ef94632aa1c491a SHA-256: e28c5bd3da591dc917cf9c280febd0b3413ac32184559a1e3b309105c70cff5b
96 Risk Score

Malware Insights

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

The PDF file contains numerous embedded URLs, many of which point to disposable hosting or compromised CMS upload directories, indicating a link farm designed to redirect users to malicious sites. The ML classifier strongly flagged this PDF as malicious, and the heuristic firings confirm its nature as a link farm, likely intended for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

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://synerhu.ru/uplcv?utm_term=mtb+hill+bike+rider+mod+apk PDF link annotation
    • http://optimaglobal.net/ckupload/files/juzokorujimuzubexisiv.pdfIn PDF document text
    • https://vhssirimpanam.org/ckfinder/userfiles/files/4798310995.pdfIn PDF document text
    • https://daaeportrett.no/upload/file/44157796185.pdfIn PDF document text
    • https://niboparis.com/upload/fckeditor/files/kolujivegoxobena.pdfIn PDF document text
    • https://gitedu.in/ckfinder/userfiles/files/xejogenunowopolopad.pdfIn PDF document text
    • http://przystaneknida.pl/data/aktualnosci_imgs/file/mowobudotukidenibugeni.pdfIn PDF document text
    • https://red-adlay.com/upload/files/16075001305.pdfIn PDF document text
    • https://chupwo.com/editor_upload/file/melosonekoger.pdfIn PDF document text
    • http://gdlejia.com/uploadfile/files/20210921_104955.pdfIn PDF document text
    • https://apatity.verlauf-ekb.ru/admin/ckfinder/userfiles/files/mufigu.pdfIn PDF document text
    • http://t-cso.com/upload/file_folder/file/jigitukekisubojilu.pdfIn PDF document text
    • https://goodline.by/userfiles/file/48916794951.pdfIn PDF document text
    • https://nmg.lv/img/uploads/files/43531199495.pdfIn PDF document text
    • http://www.fattyweng.com.sg/wp-content/plugins/formcraft/file-upload/server/content/files/161361cc457342---minowefikukowewidovise.pdfIn PDF document text
    • https://akvaguru.hu/user/file/17150101253.pdfIn PDF document text
    • http://jar-ted.pl/file/pimoniguzomizipekanafa.pdfIn PDF document text
    • http://www.canadiantreasurer.com/wp-content/plugins/formcraft/file-upload/server/content/files/16144c6fc6be32---xuzumotaxiw.pdfIn PDF document text
    • http://longarmquiltacademy.net/fckeditor/userfiles/file/derorusugonopal.pdfIn PDF document text
    • https://www.sussexweddingservices.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1613d426d4bf3d---risivibimis.pdfIn PDF document text
    • http://studiopetrilli.it/userfiles/files/77248713162.pdfIn PDF document text
    • http://wksystems.net/HotelEstimator/userfiles/file/49594296025.pdfIn PDF document text
    • https://santa.sg/images/users/00000000/files/fejedowawunekujowak.pdfIn PDF document text
    • https://ezsprinting.com/userfiles/file/wopamomivoweruzewe.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_off0000ae8f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAE8F 15724 bytes
SHA-256: 4a2d4d73c7e653d23d51a9566b1b0391fd61f8bd06d472e5a2775f5f6079f6f1
font_01_sfnt_off0000d58c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD58C 10612 bytes
SHA-256: 411378c4fb6e5dd62dfe6b150041afc8a26f0123823a2b063c7f3004b089c8dd
font_02_sfnt_off0000ed84.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED84 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1