Malicious PDF — malware analysis report

Static analysis result for SHA-256 51bd03243a95d72a…

MALICIOUS

PDF

89.1 KB Created: 2021-07-22 12:14:30 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-13
MD5: e83bea54f7fd6f4db0f2b5a96b62b2db SHA-1: b31c6f5bfcf95d4c55f9ff763366a108b9ae247a SHA-256: 51bd03243a95d72ab5ebccf664e10ce474befe4628beb57d588620b0b89f817c
156 Risk Score

Malware Insights

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

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm pointing to compromised CMS upload storage and disposable hosting, suggesting a phishing or malware distribution scheme. The document body was unreadable, but the presence of numerous unknown URLs strongly supports the link farm attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9954

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://jetzterstrecht.hamburg/wp-content/plugins/super-forms/uploads/php/files/l2k6s8qrd33mlmfm8uanv2h0d2/31231951817.pdf In PDF document text
    • http://iwaandccareunion.com/clients/57137/File/70792365925.pdfIn PDF document text
    • https://nobleanimalsanctuary.org/wp-content/plugins/super-forms/uploads/php/files/tmp/38053093112.pdfIn PDF document text
    • https://ngoctraithaibinhduong.com/uploads/news_file/xusimalugagilepovadobud.pdfIn PDF document text
    • http://progfin.pl/userfiles/file/susedekiti.pdfIn PDF document text
    • https://hirurgija.me//files/1651184739.pdfIn PDF document text
    • https://metroguards.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160b710d556ae2---xoresokagawepevexufado.pdfIn PDF document text
    • http://www.malagatour.es/ckfinder/userfiles/files/96460977126.pdfIn PDF document text
    • http://www.idenet.net/wp-content/plugins/formcraft/file-upload/server/content/files/16087f00742388---porunes.pdfIn PDF document text
    • http://andreevmag.com/wp-content/plugins/super-forms/uploads/php/files/126de314969346992ecfa5afc1ef5b65/32951004826.pdfIn PDF document text
    • https://aquariumfargo.com/wp-content/plugins/super-forms/uploads/php/files/f4df969788a3a31a2e0aad9a4cdba906/ninelamotatewujusuti.pdfIn PDF document text
    • http://gitishahjahanpur.org/ckfinder/userfiles/files/dudola.pdfIn PDF document text
    • http://osrclass1967.com/clients/8/84/84e84eb3bb32f45446e669e24fea3ebc/File/pafuwozewowulimopusopo.pdfIn PDF document text
    • https://oiweld.com/wp-content/plugins/super-forms/uploads/php/files/987c95ad4ad080c6ccdf8bc7556b8734/lojaxekemotove.pdfIn PDF document text
    • http://sip7.online/wp-content/plugins/super-forms/uploads/php/files/f451992332c7c2e58798d520fa16e0df/fobasanesidasisawewow.pdfIn PDF document text
    • http://criollo-cocoa.com/userfiles/file/tunogozosekowikuzimirib.pdfIn PDF document text
    • http://chicohigh1987.com/clients/47015/File/73140292089.pdfIn PDF document text
    • http://bonapartefamilynetwork.com/clients/7/7d/7d081654635712149502d88e72c54c2d/File/wegeselikizamew.pdfIn PDF document text
    • https://nilsagame.com/calisma2/files/uploads/16226722825.pdfIn PDF document text
    • http://aeskulap24h.com/wp-content/plugins/formcraft/file-upload/server/content/files/160e975506f9cc---nexafelize.pdfIn PDF document text
    • http://acetuitioncentre.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160e552efbdaeb---nukunimenizotakojegi.pdfIn PDF document text
    • http://oio.cn/uploadfiles/files/fitas.pdfIn PDF document text
    • http://stkvn.ru/wp-content/plugins/super-forms/uploads/php/files/e76802981bdaeef7d7c584d348603c4e/57496164711.pdfIn PDF document text
    • https://m-astar.com/UserFiles/files/wonezalupibakitarulo.pdfIn PDF document text
    • http://rentbucharest.net/images/userfiles/41369852285.pdfIn PDF document text
    • http://www.rlktechniek.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160c19bf630ebf---77663494247.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3vuEKuznOb8/uplcv?utm_term=statistical+process+control+in+quality+managementPDF 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_off0000f992.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF992 16520 bytes
SHA-256: 952e23804a8d86dc5562592efa973d3a5d13c15541cd6a673ec37fc91d4c2d92
font_01_sfnt_off000123ff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x123FF 11152 bytes
SHA-256: 03db3a3b36ec02fb0f55a36a060aa88b955043f5748778cb9b6f7cb392a3c3f2
font_02_sfnt_off00013dc0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13DC0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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