Malicious PDF — malware analysis report

Static analysis result for SHA-256 a77d533607dd6754…

MALICIOUS

PDF

89.1 KB Created: 2021-08-14 00:10:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 5f18f13f0088a26c295d4edb52f446ae SHA-1: 36819b198fcb4ad3bd1e55da824d65ae315cf72a SHA-256: a77d533607dd6754ee9bf14a1e3de02a0b4e30c9d0bb90575b577b92b261d400
136 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF contains numerous links pointing to potentially compromised websites and disposable domains, suggesting a link farm designed to distribute malicious content. The ML classifier strongly indicates maliciousness, and the presence of PDF_RANDOM_URL_LINK and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics further supports this. The primary attack pattern involves luring users to download a secondary malicious PDF.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9919

Heuristics 6

  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://a2designbg.com/userfiles/file/55120349823.pdf In PDF document text
    • http://teleinwestor.pl/userfiles/file/bigikasagegid.pdfIn PDF document text
    • http://www.pethouse.es/ckfinder/userfiles/files/8846683769.pdfIn PDF document text
    • http://minhanh.com/files/vumepiliposito.pdfIn PDF document text
    • https://boucherienabli.com/uploads/FCK_files/file/gokod.pdfIn PDF document text
    • http://fsnmmaterials.com/UPFILE/userfiles/files/65695088381.pdfIn PDF document text
    • http://thueotodn.com/uploads/image/files/9768750051.pdfIn PDF document text
    • http://yalciniskele.com/imgup/file/samudeledupigudaxagopor.pdfIn PDF document text
    • http://wahluenfty.com/userfiles/sikikonodetuguwapij.pdfIn PDF document text
    • https://1sis.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bae0acaedfb---dujekopuwobujiwovukuwi.pdfIn PDF document text
    • http://poltinka.ru/userfiles/file/fofuxi.pdfIn PDF document text
    • http://rauvuonsach.net/images/uploads/files/nukutukedezuzemiz.pdfIn PDF document text
    • https://castilloexterior.org/ckfinder/userfiles/files/xutoludovemano.pdfIn PDF document text
    • https://alllegaltask.com/wp-content/plugins/super-forms/uploads/php/files/l297g9jqaqjme9ds8qlefvjr5i/81959385130.pdfIn PDF document text
    • http://www.ncstarim.com.tr/wp-content/plugins/super-forms/uploads/php/files/4khnaanvevkrrbh9lpcbqp75r6/18853375736.pdfIn PDF document text
    • https://etcbt.com/userfiles/file/69433778398.pdfIn PDF document text
    • http://josephlillianmorrisfamily.com/clients/59960/File/42622343072.pdfIn PDF document text
    • http://moveisgarciadigital.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16088cc8a7c57a---60515306731.pdfIn PDF document text
    • http://ineke-ott.nl/keramiek-beelden-imagesfile/87365242770.pdfIn PDF document text
    • https://alkalacarservice.com/public_html/userfiles/file/81145939004.pdfIn PDF document text
    • https://www.sir.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16083d78bbff3f---30443156202.pdfIn PDF document text
    • http://bscartridge.com/pic/wivejosopop.pdfIn PDF document text
    • http://toonesk.com/upload/rokefokoxekimid.pdfIn PDF document text
    • https://lakecountyoralsurgery.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e9689656011---jomiganisurupig.pdfIn PDF document text
    • http://erfaspot.com/resimler/files/zisexugasawekuredafu.pdfIn PDF document text
    • http://brucemaymemorialgolftournament.com/clients/d/d2/d245e0393a5bbb16d67b82808c007790/File/gesulifulilite.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=reported+speech+mixed+exercises+pdf+advancedPDF 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_off0000f3a4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF3A4 18024 bytes
SHA-256: 9f2fa471e08ec00e02b0d81fd47c465c076761dd47d616d265974093e915b08b
font_01_sfnt_off000121df.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x121DF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000139f6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x139F6 11052 bytes
SHA-256: 2666cf9652def8c39df6eb6d5154c33d51132d3dcd21e69caae5f98ac30db9b9

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