Malicious PDF — malware analysis report

Static analysis result for SHA-256 8cd6364c387f7852…

MALICIOUS

PDF

81.1 KB Created: 2021-09-09 09:37:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 3c5211c0d0426a816307adfd1a0bffc4 SHA-1: 9d6ee14f03177fefe156e74a2d42727e916b585c SHA-256: 8cd6364c387f785221a9cfbc43c00845e43d985b330a6608882d23628b900bb1
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains numerous embedded URLs, many of which point to compromised CMS upload directories or disposable hosting, indicating a link farm designed to distribute malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware delivery via these external links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 6

  • 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 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://chcial.ru/uplcv?utm_term=mr+novel+online+reading PDF link annotation
    • http://vers-ma.de/userfiles/file/noranigipo.pdfIn PDF document text
    • https://lixtech.com.tw/ckfinder/ckfiles/files/gewuvakifisedaxuwugu.pdfIn PDF document text
    • http://graylegalservices.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/sizifu.pdfIn PDF document text
    • http://justsayhi365.com/uploads/file/buteleluvogujenabilumub.pdfIn PDF document text
    • https://ysh.my/userfiles/file/bedotadexalevagumu.pdfIn PDF document text
    • http://4x4autok.hu/userfiles/files/jilaxepulalukevil.pdfIn PDF document text
    • http://slowjamsundays.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138c0b5c6732---40780228371.pdfIn PDF document text
    • https://pasarangroup1.com/contents/files/wupok.pdfIn PDF document text
    • https://stephankeppel.com/userfiles/file/8303640292.pdfIn PDF document text
    • https://costumeworld.com/wp-content/plugins/formcraft/file-upload/server/content/files/161324ab7c5104---46469115149.pdfIn PDF document text
    • https://ksmt.edu.np/assets/ckfinder/userfiles/files/49034451024.pdfIn PDF document text
    • http://alompar.hu/uploads/content_files/files/lawaganufis.pdfIn PDF document text
    • http://xn--or3bo5mvlb.com/data/editor/file/16467870129.pdfIn PDF document text
    • http://studiolegalebisantis.it/userfiles/files/59822342244.pdfIn PDF document text
    • https://hse.tw/upload/file/68777843281.pdfIn PDF document text
    • http://billagelaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/nodudoliluzafaba.pdfIn PDF document text
    • http://ekopaczka.pl/imgbrama/files/88048228613.pdfIn PDF document text
    • http://wideanglepackaging.com/ckfinder/userfiles/files/61453294637.pdfIn PDF document text
    • https://intelean.com/wp-content/plugins/formcraft/file-upload/server/content/files/161308ec84f7b5---4559167847.pdfIn PDF document text
    • https://www.onestopnaturalstore.ca/wp-content/plugins/super-forms/uploads/php/files/4p4pio3v4s6sjf1712c2p94h9n/58836427424.pdfIn PDF document text
    • http://lambanghieuquangcaogiare.net/vietkiendo/upload/file/69051298675.pdfIn PDF document text
    • http://ytlcases.com/userfiles/file/tibugalabazoxoninadulif.pdfIn PDF document text
    • https://unitedcardsolutions.com/wp-content/plugins/formcraft/file-upload/server/content/files/161395a9a98264---7945555925.pdfIn PDF document text
    • https://tekdalyapi.com/upload/ckfinder/files/48799307000.pdfIn PDF document text
    • http://studiogalata.it/userfiles/files/gozobiserubepisabejajuve.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_off0000db57.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB57 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f369.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF369 17348 bytes
SHA-256: e5e90ba1b69632e65d961f64cd055e8c74390b02376a0447fac749b63e0c4342
font_02_sfnt_off00012017.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12017 10216 bytes
SHA-256: 008df8d523a5bb4f60db7640dc235473890f5233618fd4f8d3ba7d8400d33980