Malicious PDF — malware analysis report

Static analysis result for SHA-256 851844b665f7c60f…

MALICIOUS

PDF

81.3 KB Created: 2021-09-21 14:51:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 95ff8f5785a45ab718ce856acce7f6d4 SHA-1: 6897d70045d1fd13c2d9b2a5c82a9a71fbe53328 SHA-256: 851844b665f7c60f167ea4912205eda6d9155e43367e0caabb3369248b929cdd
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically identified as a phishing trojan. It contains numerous embedded URLs, many of which point to compromised CMS upload storage or disposable hosting, suggesting a link farm designed to redirect users. The document body is heavily obfuscated and unreadable, but the presence of multiple suspicious URLs and the high ML score indicate a malicious intent to lure users to external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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 http://costruzionibulagna.it/userfiles/files/lokegidebafazi.pdf In PDF document text
    • http://dichvumucin.com/upload/ckupload/files/rosiroxasavo.pdfIn PDF document text
    • https://cafesca.info/ckfinder/userfiles/files/vutoramosukejanakat.pdfIn PDF document text
    • https://mokshadhamnepal.org/userfiles/files/52686318868.pdfIn PDF document text
    • http://teamhead.net/userfiles/file/25949634886.pdfIn PDF document text
    • https://www.kiteschule-kiel.de/wp-content/plugins/formcraft/file-upload/server/content/files/16133bb4a93eea---94047505105.pdfIn PDF document text
    • http://www.megasaludips.com/wp-content/plugins/formcraft/file-upload/server/content/files/16132e80ed58b6---92723863318.pdfIn PDF document text
    • http://gidromall.ru/img/uploads/file/95711719218.pdfIn PDF document text
    • https://k-newsletter.com/ckupload/files/5174746019.pdfIn PDF document text
    • http://hillsdalehorseboarding.com/ckfinder/userfiles/files/13860707412.pdfIn PDF document text
    • http://indiebookoftheday.com/wp-content/plugins/formcraft/file-upload/server/content/files/16144e93cda744---91465004880.pdfIn PDF document text
    • http://botaierpharm.com/upload/files/43435152651.pdfIn PDF document text
    • https://sharzh-ufa.ru/wp-content/plugins/super-forms/uploads/php/files/45b80e83411c5fbb460471db7946f862/49726961314.pdfIn PDF document text
    • http://www.pethouse.es/ckfinder/userfiles/files/8649633605.pdfIn PDF document text
    • http://www.sictombbi.fr/ckfinder/userfiles/files/82933202593.pdfIn PDF document text
    • http://krindustria.com.br/site/wp-content/plugins/formcraft/file-upload/server/content/files/161390124bf90c---77913242943.pdfIn PDF document text
    • http://fosterfreezesantarosa.com/uploads/files/16023106851.pdfIn PDF document text
    • https://eminentland.com/admin/userfiles/files/vizojilexotimu.pdfIn PDF document text
    • http://xsteelstock.com/d/files/gerevavu.pdfIn PDF document text
    • https://jahanchart.ir/data/files/file/divimeworopaxobo.pdfIn PDF document text
    • http://greenglobepms.com/uploads/kenosukowigininid.pdfIn PDF document text
    • http://ailizia.com/userfiles/bakafefo.pdfIn PDF document text
    • https://kakvkusno26.ru/wp-content/plugins/super-forms/uploads/php/files/3550d20c3259e6d6deb924ed25c44b51/28395223316.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/fzgW7-mxBc0/uplcv?utm_term=king+of+fighters+12+apkPDF 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_off0000d42d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD42D 10848 bytes
SHA-256: 61d356ff75193378e760c0e4e2988dea2fba689856cffb779fd1265b17f60630
font_01_sfnt_off0000ed45.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED45 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010557.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10557 19500 bytes
SHA-256: b7345cf8f0f90a48e9aa28550d02161a3ff73be90e68751ab4011ce1376215fa