Malicious PDF — malware analysis report

Static analysis result for SHA-256 357c582c1f2cf535…

MALICIOUS

PDF

83.6 KB Created: 2021-09-18 23:15:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: e20cc982e5a21201d2ea8147cc1f1dab SHA-1: 5dd7b7f685bb5cc35688a78c6229e875c4d11472 SHA-256: 357c582c1f2cf5354170bc52204373c3c7f06e96cc645c68e97639a4437f49d5
96 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised CMS upload directories, indicating a link farm designed to distribute malicious content or phish users. The ML classifier strongly flagged this PDF as malicious, supporting the assessment of a malicious intent. No scripts were extracted, and the document body was unreadable, so the rationale is based on the URL analysis and heuristic firings.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9912

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 http://kursadowicz.pl/Upload/file/87683169738.pdf In PDF document text
    • https://merlak.ru/userfiles/file/vexebonarowuvutoderorava.pdfIn PDF document text
    • http://vhktn.at/images/content/files/96335001664.pdfIn PDF document text
    • https://www.totalblissbeauty.com.au/application/third_party/ckfinder/userfiles/files/47602925956.pdfIn PDF document text
    • https://pluckywize.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613b914c89e1b---1626640680.pdfIn PDF document text
    • http://okna-stv.ru/userfiles/files/dufeganep.pdfIn PDF document text
    • https://kvartira-zalog.ru/wp-content/plugins/super-forms/uploads/php/files/ffb2ebd88bd3a47a9c462e23a80ff41a/fikoberu.pdfIn PDF document text
    • https://lockerova.eu/admin/upload/documents/sumixatazexali.pdfIn PDF document text
    • https://bokseinstituttet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/161324c451d693---wujiweza.pdfIn PDF document text
    • https://www.dynasil.com/wp-content/plugins/super-forms/uploads/php/files/a277d9087e90e267700fa0ffb191a165/37449566014.pdfIn PDF document text
    • http://wu-pao.com/upfiles/editor/files/badako.pdfIn PDF document text
    • http://toflight.mobi/attachment/ckeditor/files/d4cd510e59ca0226f3692eed96a77742.pdfIn PDF document text
    • http://ndfeef.com/radiant/mechimobiles/userfiles/files/86914419921.pdfIn PDF document text
    • https://ans5680.preneed91.com/upload/files/zatumot.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/16130fe0c172ac---43115822225.pdfIn PDF document text
    • http://www.cenlaenvironmental.com/siteuploads/editorimg/file/77497399919.pdfIn PDF document text
    • https://atkarisuli.hu/userfiles/file/zibego.pdfIn PDF document text
    • http://defhjdrjioo.friend-match.com/upload/files/tuzom.pdfIn PDF document text
    • https://tarzminder.com/resimler/files/sugabewijaxojonane.pdfIn PDF document text
    • http://mya1fc.com/files/ckuploads/files/55661268735.pdfIn PDF document text
    • http://florylaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/27861096243.pdfIn PDF document text
    • http://myphamlulanjina.com/upload/files/bolel.pdfIn PDF document text
    • http://sicilyontable.it/userfiles/files/27193074243.pdfIn PDF document text
    • http://cluboutletmoto.net/campannas/file/viketu.pdfIn PDF document text
    • https://egyediajandekotletek.hu/mvc/userfiles/file/silebafidejudupufu.pdfIn PDF document text
    • https://bikeid.net/ckfinder/userfiles/files/28128662964.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=index+of+the+agents+of+shieldPDF 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_off0000deab.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDEAB 18308 bytes
SHA-256: a4b964118d70924e15c6c5dcd0b662527fe062dd7f91d4618f0292bdac869ff6
font_01_sfnt_off00010e7d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10E7D 10588 bytes
SHA-256: 5f3bab707feb56be490f58ecaa017d25e5131fdf18dad252ca3be45c5ee9048a
font_02_sfnt_off00012668.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12668 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1