Malicious PDF — malware analysis report

Static analysis result for SHA-256 fdcbce3f3325275e…

MALICIOUS

PDF

93.7 KB Created: 2021-09-11 13:29:23 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 621cabea58f142f92a7931184f07dabd SHA-1: 7b79c33445f1568e75827537bca9be11c31a10ac SHA-256: fdcbce3f3325275e4fcb669bd0e8103dc105ced16c51fdf47dbd01ecca040c0d
174 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file that contains embedded JavaScript, which is often used to redirect users to malicious websites. Several heuristics indicate the presence of link farms and compromised CMS uploads, suggesting an attempt to distribute malicious content or phish for information. The ClamAV detection further confirms its malicious nature, likely as a phishing or trojan delivery mechanism.

Machine Learning

  • Nyx PDF Classifier suspicious score 0.3935

Heuristics 8

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://centar-znr-zop.hr/wp-content/plugins/formcraft/file-upload/server/content/files/16135074a3f40e---dadiwi.pdf In PDF document text
    • http://www.park-seversk.ru/other/js/ckfinder/userfiles/files/xaditamagiletuvekigiwep.pdfIn PDF document text
    • https://shellserva.nl/docs/Image/file/50374998615.pdfIn PDF document text
    • http://hflbdq.com/uploads/file/040512116518.pdfIn PDF document text
    • https://www.fyna.com.au/application/third_party/ckfinder/userfiles/files/60079246519.pdfIn PDF document text
    • http://noithatachau.vn/webroot/img/files/zobamugirasusamanukexugep.pdfIn PDF document text
    • http://baharev76.ru/userfiles/file/xejized.pdfIn PDF document text
    • http://dc-42351dc5a6b3.prshots.es/uploads/userfiles/1630493241/files/gupidofenagajufiwazejeziv.pdfIn PDF document text
    • https://koparieshorvathbusz.hu/files/file/kujituvuveta.pdfIn PDF document text
    • https://bozoklar.org/ckfinder/userfiles/files/futuvodumuxupolij.pdfIn PDF document text
    • https://grandplaza.bg/uploads/assets/file/86302940651.pdfIn PDF document text
    • https://kvizek.hu/ckfinder/userfiles/files/novexibimuve.pdfIn PDF document text
    • http://ambulatorioveterinariosantanna.eu/userfiles/files/73405143934.pdfIn PDF document text
    • https://badeluxe.com/userfiles/files/96948415264.pdfIn PDF document text
    • https://astoriareiki.com/wp-content/plugins/super-forms/uploads/php/files/7f3538162661f0a9c29d6a474f235f43/64123234287.pdfIn PDF document text
    • https://unitedcardsolutions.com/wp-content/plugins/formcraft/file-upload/server/content/files/161352fd4e36f1---pokowabojine.pdfIn PDF document text
    • https://adtw1.elfjane.com/ckfinder/userfiles/files/81636426077.pdfIn PDF document text
    • https://techlan.pl/files/file/tubixomedofevidegadalowe.pdfIn PDF document text
    • http://cosonhuath.com/hinhanh_fckeditor/file/2834191278.pdfIn PDF document text
    • https://astefin.ro/ckfinder/userfiles/files/35225470302.pdfIn PDF document text
    • https://hgindustrial.eu/userfiles/files/38325901405.pdfIn PDF document text
    • http://tunapvietnam.thietbiotoviet.com/Images_upload/files/baludifebineg.pdfIn PDF document text
    • http://jiehuist.com/userfiles/files/lawilodotojosevul.pdfIn PDF document text
    • http://basumati.com/app/webroot/ckfinder/userfiles/files/pogufaf.pdfIn PDF document text
    • https://noelex22.org/userfiles/file/rofedo.pdfIn PDF document text
    • http://www.udelimpa.es/ckfinder/userfiles/files/sabizasimometifapabawe.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/Om9ozkHLxGw/uplcv?utm_term=play+online+games+and+win+real+cashPDF link annotation
    • 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_off00011206.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11206 10920 bytes
SHA-256: 49aa324fb6bfeec97f5bdd2e31a40fa5459ab4f6b1aeb0d5c3a7eddbdde5ca5b
font_01_sfnt_off00012af8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12AF8 17412 bytes
SHA-256: a34ca17b5f36b01788b98095bf2454e83a5c2304787b6b57dd40083f072d3e2c
font_02_sfnt_off000158a0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x158A0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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