Malicious PDF — malware analysis report

Static analysis result for SHA-256 98f87aa8fc34b672…

MALICIOUS

PDF

72.2 KB Created: 2021-09-08 20:53:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 172d6504e935a56553b20348be2840a7 SHA-1: 73cbfd24a201b56aa6a0928cc014ac5956b9e3b3 SHA-256: 98f87aa8fc34b672b81029af01aa5f7501155eeecabbe98bace2df35ab9853aa
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was flagged as malicious by ClamAV and an ML classifier. It contains numerous embedded URLs, many of which are hosted on compromised CMS upload storage or disposable domains, suggesting a link farm designed to redirect users. The primary URL, 'https://inwebjor.ru/uplcv?utm_term=microbiology+an+introduction+11th+edition+study+guide+pdf', appears to be a lure, using a specific search term to entice clicks. While no scripts were explicitly extracted, the nature of the URLs and the PDF structure strongly indicate a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://inwebjor.ru/uplcv?utm_term=microbiology+an+introduction+11th+edition+study+guide+pdf PDF link annotation
    • http://www.ashtralmedia.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613627a4c66e2---93061840311.pdfIn PDF document text
    • http://henzefashion.com/userfiles/file/wofuvanasamoniden.pdfIn PDF document text
    • http://a-xian-coat.com/uploads/files/202109061531562770.pdfIn PDF document text
    • http://polipack.ru/content/file/mogakekusipovufiwe.pdfIn PDF document text
    • http://gewald.ru/content/Files/fulewitezo.pdfIn PDF document text
    • https://stpatswatertown.org/ckfinder/userfiles/files/31138324488.pdfIn PDF document text
    • http://elcolono.net/userfiles/files/58790595693.pdfIn PDF document text
    • https://www.glasswindowequipment.com/wp-content/plugins/super-forms/uploads/php/files/898fd7edf4758d4d38b0d24eb4fe76a8/74593313490.pdfIn PDF document text
    • http://diadiemvui.com/upload/files/71504869335.pdfIn PDF document text
    • https://sikdercollegeofpharmacy.com/scp/ckfinder/uploads/userfiles/files/jawibabexidimimozez.pdfIn PDF document text
    • http://osheamaloneynylaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/gadexezegapotulabij.pdfIn PDF document text
    • https://fnb-concepts.com/images/uploads/files/4741754723.pdfIn PDF document text
    • https://chineseclothingonline.com/File/85407791589.pdfIn PDF document text
    • https://osakadentalcare.com/contents/files/rizaxujupijekonisazifajur.pdfIn PDF document text
    • http://pbhdom.eu/userfiles/file/83674708325.pdfIn PDF document text
    • http://tofuyatogo.com/uploads/files/fedudikurub.pdfIn PDF document text
    • http://www.samuitns.com/image/upload/File/24908110452.pdfIn PDF document text
    • http://6nergy.fr/6nergy/sites/default/user/file/sofowidejezomujiperopo.pdfIn PDF document text
    • http://resortcrimea.com/ckfinder/userfiles/files/tuxarofemogeledorenevaxod.pdfIn PDF document text
    • https://christembassybarking.org/wp-content/plugins/super-forms/uploads/php/files/44bc92be52a1b239761c08a62390de7a/buxapojezelusoref.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_off0000b500.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB500 16292 bytes
SHA-256: b636d73578dfb4f78808512c47968576f36b85c3071812b52f01161ab50ba43f
font_01_sfnt_off0000df19.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF19 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f730.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF730 11300 bytes
SHA-256: 6b6baf01b50937b0d670282f4d92466579a0b4dcab8f2690b31e30d451c030b7