Malicious PDF — malware analysis report

Static analysis result for SHA-256 d73d78779e9d8c46…

MALICIOUS

PDF

88.9 KB Created: 2021-08-20 07:25:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 9aa3059f5e437e3a76707a6966fd99ee SHA-1: e1607110502768fedfb9153dd7ab971ca0c0c0b4 SHA-256: d73d78779e9d8c4679e7df15a589bbede3c64b0db00f4146f3a019c1fc3b2c23
156 Risk Score

Malware Insights

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

The PDF contains a link farm with numerous external URLs, many pointing to compromised CMS upload directories. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The document body is heavily obfuscated and unreadable, providing no direct clues to its purpose beyond the heuristic findings.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

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://kiuanai.com/userfiles/file/91344055336.pdf In PDF document text
    • http://aygroupmuh.com/image/files/5427805359.pdfIn PDF document text
    • http://zakuskymoser.cz/www/ckfinder/userfiles/files/59434861162.pdfIn PDF document text
    • https://drivingschoolofnorthtexas.com/wp-content/plugins/formcraft/file-upload/server/content/files/160773e05bb0b7---nigul.pdfIn PDF document text
    • http://www.dkmodels.net/ckfinder/userfiles/files/gefefojonusi.pdfIn PDF document text
    • https://www.mnogotrop.com/ckfinder/userfiles/files/68101737451.pdfIn PDF document text
    • http://krishikhabar.net/assets/ckfinder/core/connector/php/uploads/files/48034046234.pdfIn PDF document text
    • http://www.holderit.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a440ca56ee5---lanoxaterivob.pdfIn PDF document text
    • https://thewentworthco.com/wp-content/plugins/super-forms/uploads/php/files/m1q93b01bnvres3ha5f3fp6604/90649786654.pdfIn PDF document text
    • http://www.oknookna.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1611a1774e463d---42039561010.pdfIn PDF document text
    • https://comtraining.cl/userfiles/files/jonaxikilojidojovoxiwu.pdfIn PDF document text
    • https://www.yoursurveysurveyors.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160a2811a40be1---zezerarujuvojebatagimov.pdfIn PDF document text
    • https://songhong-thudo.com/img/files/80190472880.pdfIn PDF document text
    • http://radissonhoteltraining.com/userfiles/file/zorejibufimivanimofuzolep.pdfIn PDF document text
    • http://simpli.ie/survey/userfiles/files/lowumud.pdfIn PDF document text
    • https://mygamedaysports.com/wp-content/plugins/super-forms/uploads/php/files/dfcb6a9140e3d6d3bf79b66311817b5d/xamuvefo.pdfIn PDF document text
    • https://tucsonhomewindowtint.com/wp-content/plugins/super-forms/uploads/php/files/ccd48fe828c0449fd2ea91653ebbcd45/1546818734.pdfIn PDF document text
    • http://anhuifan.com/upload_fck/file/2021-5-26/20210526150849422020.pdfIn PDF document text
    • https://law.com.sg/wp-content/plugins/super-forms/uploads/php/files/8cb30acec77ccb1ae2900d21ce453e05/51267783353.pdfIn PDF document text
    • https://carthink.org/wp-content/plugins/formcraft/file-upload/server/content/files/160a1edb0af6e3---56622127320.pdfIn PDF document text
    • https://www.unicodesystems.com/wp-content/plugins/super-forms/uploads/php/files/dl69u3c88ps96112qfb198utb1/39016573491.pdfIn PDF document text
    • http://954move.com/clients/4890/File/54247515638.pdfIn PDF document text
    • https://tatsolarlight.com/uploads/files/76590773375.pdfIn PDF document text
    • http://www.radioemka.com/wp-content/plugins/formcraft/file-upload/server/content/files/160967bc5422a0---51491233746.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/DOqCt-cVA4I/uplcv?utm_term=how+to+make+frosting+thicker+without+powdered+sugarPDF 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_off0000f593.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF593 16776 bytes
SHA-256: c779f7ad2200948c0576e8e0c0d575ca68e621b8b87369312e5d971363ac78bb
font_01_sfnt_off00012114.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12114 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001392b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1392B 11288 bytes
SHA-256: 4300f9e390adf9b10fb0828dbbc8fa991243a96fc8eb493469260b39d516e89c