Malicious PDF — malware analysis report

Static analysis result for SHA-256 cb840e2cc06e1a2e…

MALICIOUS

PDF

71.3 KB Created: 2021-09-12 13:32:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: d3d6686b94308d93cefd2e1d34af7fc3 SHA-1: babfab969129a60f44674c5dcbd74738d99b7d4b SHA-256: cb840e2cc06e1a2ed933172a411e4832a65111c0f5911b4feb01de4c4e1f9429
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript T1203 Exploitation for Client Execution

The PDF contains embedded JavaScript and multiple external URIs, many of which point to compromised WordPress sites acting as a link farm. The heuristic PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM indicate a phishing or malware distribution scheme. The ML classifier and ClamAV detection strongly suggest malicious intent, likely to trick users into downloading further malware disguised as a Flash Player update.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

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 https://medvor.ru/uplcv?utm_term=flash+player+puffin PDF link annotation
    • http://tjsyjdq.com/v15/Upload/file/2021931111116592.pdfIn PDF document text
    • https://chulintemple.org/CKEdit/upload/files/jikojuvetijogalujebano.pdfIn PDF document text
    • http://revucue.com/ckfinder/userfiles/files/85144615878.pdfIn PDF document text
    • http://aal.tw/uploads/htmlupload/files/85069013212.pdfIn PDF document text
    • http://partner-support.net/user_data/userfiles/files/87038085396.pdfIn PDF document text
    • http://argentum.com/wp-content/plugins/super-forms/uploads/php/files/kd2teu4hnrf6p18hmcfvm52atj/dorevunikaxitadedefesevu.pdfIn PDF document text
    • http://proxima-design.cz/files/file/41463792610.pdfIn PDF document text
    • http://sangjeom.com/userfiles/file///vowuputerosapupezeve.pdfIn PDF document text
    • https://imapcb.org/wp-content/plugins/super-forms/uploads/php/files/ffe8be36de00e04d33fc71632accf800/56214053944.pdfIn PDF document text
    • https://polinagerz.ru/wp-content/plugins/super-forms/uploads/php/files/04b55f2ui3nfhnv8lk46b9is03/kudunoguvuw.pdfIn PDF document text
    • https://snpwachq.com/files/js/ckfinder/userfiles/files/27256838108.pdfIn PDF document text
    • https://dfa-finanz.de/wp-content/plugins/formcraft/file-upload/server/content/files/16136cd3f862b9---fabufofujiliwu.pdfIn PDF document text
    • https://komunalno-vrgorac.hr/files/jevogideteroz.pdfIn PDF document text
    • http://karmakonnect.org/DrumiBhatt/karmakonnect.org/Final/ckeditorimage/files/kurijukonamabedutasi.pdfIn PDF document text
    • http://xn--rssx31a7tec6p.com/upload/userfiles/files/20210912140329.pdfIn PDF document text
    • http://shengyaweb.com/uploadfile/file/2021090407494374.pdfIn PDF document text
    • http://graylegalservices.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/zejukusototowepakozeru.pdfIn PDF document text
    • https://thesmithgrouphouston.com/wp-content/plugins/super-forms/uploads/php/files/2a8a3d6a4817e991ce85e5325e107109/29253026683.pdfIn PDF document text
    • http://bfr-bialapodlaska.pl/userfiles/file/23519600999.pdfIn PDF document text
    • https://aznamaste.com/ckfinder/userfiles/files/wuguwaxiwal.pdfIn PDF document text
    • https://myparrotfood.com/user_files/files/1596004063.pdfIn PDF document text
    • https://claudiodituri.it/uploads/nudogiwixesavuxixug.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_off0000b4d1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB4D1 10428 bytes
SHA-256: 98e1f3e20be305e31f1efcbd3112cbc25722d0e70b1b334634e01074e02a8374
font_01_sfnt_off0000cc56.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCC56 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e468.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE468 17060 bytes
SHA-256: d725506833bae78ba7db8ef4480c2b31b9218f2ece611336f7bb4be3a5696c08

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