Malicious PDF — malware analysis report

Static analysis result for SHA-256 b1d388a66f159111…

MALICIOUS

PDF

85.6 KB Created: 2021-08-11 17:30:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: fb9e3e9bdbace90dd67ea6e35083f581 SHA-1: f791c0fac27e7d99dca484ff0eac37b5fbc40c90 SHA-256: b1d388a66f159111b455ac46c085ef4a89c62b7664ce82c24dd292065d59e1f9
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF containing embedded JavaScript, which is a common technique for delivering malicious content. Heuristics indicate it's part of a link farm pointing to compromised WordPress upload storage and disposable hosting, suggesting an attempt to obscure the true malicious destination. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://kimhoatra.com/upload/fckimagesfile/runezedu.pdf In PDF document text
    • http://burningspearmarketplace.com/js/ckfinder/userfiles/files/10889552302.pdfIn PDF document text
    • http://archinfo.ru/uploads/file/kiruka.pdfIn PDF document text
    • http://mas.vacations/wp-content/plugins/formcraft/file-upload/server/content/files/160a15a4ccdf70---dogosuximazox.pdfIn PDF document text
    • https://euroialinsol.ro/userfiles/file/50386240329.pdfIn PDF document text
    • https://livingcircles.ch/wp-content/plugins/formcraft/file-upload/server/content/files/160865cc6824e7---19054392279.pdfIn PDF document text
    • https://cradlegold.com/wp-content/plugins/super-forms/uploads/php/files/cr70qh2jljqf7q7qua46rt5e7d/2976098885.pdfIn PDF document text
    • http://itnetworkconsultingsf.com/helpdesk/app/webroot/img/userfiles/files/35791597611.pdfIn PDF document text
    • http://xn--80aaae7amexjfdlfdfg.xn--p1ai/files/file/peravuwewi.pdfIn PDF document text
    • http://gostium.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607daa8ddc7a4---lalosurixubavamatofeko.pdfIn PDF document text
    • https://www.davidcosz.de/wp-content/plugins/super-forms/uploads/php/files/h6vfs13dhf7h9pjgnjfl9st2us/woladotudi.pdfIn PDF document text
    • https://cokhivietuc.com/img-vietuc/files/fujezubijizukevuragaliw.pdfIn PDF document text
    • http://rszm88.com/upfolder/e/files/20210629052203.pdfIn PDF document text
    • http://kwik-it.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160b3b3b871b41---59958247414.pdfIn PDF document text
    • https://www.lipfish.no/wp-content/plugins/formcraft/file-upload/server/content/files/160af76303fa2f---32117763941.pdfIn PDF document text
    • http://edwardlankin.com/clients/86087/File/59150280233.pdfIn PDF document text
    • https://taevlingar.se/images/pages/file/82750158752.pdfIn PDF document text
    • https://askopenko.com/wp-content/plugins/super-forms/uploads/php/files/a53d1519a3794a30f50f71ff6c7e0286/19543750919.pdfIn PDF document text
    • https://kvgrup.com.ua/wp-content/plugins/formcraft/file-upload/server/content/files/1607bba41266c5---23312352794.pdfIn PDF document text
    • https://www.auto-ecole-acm.com/ckfinder/userfiles/files/23537386701.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/fzgW7-mxBc0/uplcv?utm_term=actividades+de+sujeto+y+predicado+para+quinto+de+primariaPDF 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_off0000e67d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE67D 11168 bytes
SHA-256: 5d680d1ec3b6f65b2c9ece135b0296445783be5a00a9f9ffbc38627aaaf1af26
font_01_sfnt_off00010061.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10061 17968 bytes
SHA-256: faf03669a8d7ed26f7e78d6998df3d61f1363978d04c17f4f0dbd292e9053ff4
font_02_sfnt_off00012d9a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12D9A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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