Malicious PDF — malware analysis report

Static analysis result for SHA-256 91cc3bf875bf319d…

MALICIOUS

PDF

82.7 KB Created: 2021-09-07 17:12:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 14e2117a35d4d20c204318abe3208da0 SHA-1: a5e11d43cb48aedc0aa877d422612f6fa15ac26a SHA-256: 91cc3bf875bf319db8dcdd72ef50c9b1570f0d8cf27125737c778600add6a7ec
156 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ML classifiers and ClamAV, indicating a phishing or trojan threat. It functions as a link farm, with numerous embedded URLs pointing to various websites, some of which are hosted on compromised CMS upload directories. This suggests an attempt to lure users to malicious sites for further exploitation.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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 http://teraval.cz/res/file/ruvotimena.pdf In PDF document text
    • http://backyardreleaf.ca/clients/6/6a/6a4eaaf8452764cb6fc14c9064ed0c71/File/nuvezetominuvu.pdfIn PDF document text
    • http://mkngsp.ru/upload/files/vasijo.pdfIn PDF document text
    • https://ewms.vn/wp-content/plugins/super-forms/uploads/php/files/ej0s9inc85p18cb1h5m0as85mu/soberijafumuxel.pdfIn PDF document text
    • https://metroguards.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160bfc4947d8bb---kojojogupaxa.pdfIn PDF document text
    • https://vanrun-it.nl/userfiles/files/kirarusobifirogisur.pdfIn PDF document text
    • https://xlux.vn/wp-content/plugins/super-forms/uploads/php/files/gilmqma4gjqnrthufkdr9vp065/pozojedunuzunojo.pdfIn PDF document text
    • https://www.waterlooarmsnewforest.co.uk/wp-content/plugins/super-forms/uploads/php/files/a970692ebf9ab913defe76da7a89f785/resutidalufedifi.pdfIn PDF document text
    • http://www.valaisconsulting.ch/file/gazom.pdfIn PDF document text
    • http://yalcinsezer.com/upload/ckfinder/files/81435694431.pdfIn PDF document text
    • http://tachikawa-derma.biz/ckfinder/userfiles/files/banizilikuguzugenedo.pdfIn PDF document text
    • https://cal.lighting/wp-content/plugins/super-forms/uploads/php/files/3768fb020fe81eb805c32866384d02b9/fejatafogu.pdfIn PDF document text
    • https://mebelpozakazu.ru/wp-content/plugins/super-forms/uploads/php/files/5cbfde620eac97e5c25897dd62141454/vobix.pdfIn PDF document text
    • https://www.llgnjinc.com/wp-content/plugins/super-forms/uploads/php/files/d12e4edefcc537bbc8f63d33d765fe06/72525864961.pdfIn PDF document text
    • http://pc580.cn/upload_fck/file/2021-8-1/20210801214347580042.pdfIn PDF document text
    • http://vlajamo.cz/images/file/ganafowegerenevagal.pdfIn PDF document text
    • https://bhsbeacon.com/FCKeditor/file/gikekurusupewajavijon.pdfIn PDF document text
    • https://www.lipfish.no/wp-content/plugins/formcraft/file-upload/server/content/files/1609cb11059dbe---45334190829.pdfIn PDF document text
    • https://xn----8sbaavnccwq4am.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/1ada0d9f18e924569661c976905af671/jawinakexarab.pdfIn PDF document text
    • https://www.ediliziaindustriale.com/wp-content/plugins/formcraft/file-upload/server/content/files/16071da86eff35---lajexakujirativamolepeva.pdfIn PDF document text
    • https://ak-oroslavje.hr/files/nisuropevilalasoposite.pdfIn PDF document text
    • http://www.skupp.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160922a2254d32---nadifamiwuf.pdfIn PDF document text
    • http://discoveryenglish.org/wp-content/plugins/formcraft/file-upload/server/content/files/160bc6fe00927e---93101968577.pdfIn PDF document text
    • http://dentish.ru/ckfinder/userfiles/files/58496249478.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/YTWXjIUwRh0/uplcv?utm_term=microservices+patterns+and+best+practices+pdfPDF 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_off0000deb1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDEB1 10764 bytes
SHA-256: 486953ba46b5751922e806f71ff8498cc75a1f98a5ea88ae2e838045f639b78a
font_01_sfnt_off0000f769.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF769 17472 bytes
SHA-256: a8b03e487ffef5c886914e06c727ec9ffed98fce4f16b7db0d5f1d3304e075c7
font_02_sfnt_off000124b8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x124B8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1