Malicious PDF — malware analysis report

Static analysis result for SHA-256 cbd77d3035dc5cd4…

MALICIOUS

PDF

69.4 KB Created: 2021-10-04 07:36:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: c2dbd72c349a7e8be009bd64fe9cb67a SHA-1: 75b0c74c791f3543fcf5133bcd030e5075391a36 SHA-256: cbd77d3035dc5cd442a0777962c23995d3dadd68aa453ed5c36c88c11a57c1f1
156 Risk Score

Malware Insights

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

The PDF contains a large number of embedded URLs, many of which point to compromised websites or domains associated with link farms. The ClamAV detection and ML classifier strongly indicate malicious intent, likely related to phishing or malware delivery through these links. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing content to analyze.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9947

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://shinaval.ru/userfiles/file/sanojon.pdf In PDF document text
    • http://asu.com.vn/wp-content/plugins/super-forms/uploads/php/files/cc3q2m0m6tf901f3duo4cp034v/zezer.pdfIn PDF document text
    • https://monamifrance.com/FileData/ckfinder/files/20210920_75A70C59E6083302.pdfIn PDF document text
    • http://fitnessklub-impuls.pl/uploads/assets/file/kuzomifoxudi.pdfIn PDF document text
    • http://emannsltd.com/userfiles/89680048606.pdfIn PDF document text
    • https://stabiactiv.com/userfiles/file/7157520320.pdfIn PDF document text
    • http://ranaghatpchsschool.org/userfiles/file/39001036106.pdfIn PDF document text
    • https://businesslife.com/content/file/wosawupoz.pdfIn PDF document text
    • https://gangnampools.com/contents/files/xelewe.pdfIn PDF document text
    • http://viettelhaiphong.me/data/dulieu/files/42839909393.pdfIn PDF document text
    • https://noks.cz/wp-content/plugins/formcraft/file-upload/server/content/files/1613b99f35739b---38813644600.pdfIn PDF document text
    • https://churchosonline.com/wp-content/plugins/super-forms/uploads/php/files/15a7f8e932f1a0a2d4cb5ad712d4ca31/18416066549.pdfIn PDF document text
    • http://yakutiaprime.ru/SITE/files/editor/file/lupasazanirubivexat.pdfIn PDF document text
    • https://wolfgang-photography.com/userfiles/files/filituvu.pdfIn PDF document text
    • https://doan295doson.vn/namthuan/images/news/files/52614370104.pdfIn PDF document text
    • https://baoyi-chuck.com/ckfinder/userfiles/files/95857404273.pdfIn PDF document text
    • http://tavaszitura.eu/userfiles/files/wulilitexinitafoli.pdfIn PDF document text
    • http://modelseafarm.com/kweb/ckfinder/userfiles/files/lajowuvawivopuko.pdfIn PDF document text
    • http://www.kinoimaging.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1614bde528e22e---nutidibodelovasod.pdfIn PDF document text
    • http://www.iso-clean.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1613227e79139b---resatasubaduvusadovak.pdfIn PDF document text
    • https://inprovitcentroamerica.com/ckfinder/userfiles/files/34328164859.pdfIn PDF document text
    • https://marlin-aquarium.ru/ckfinder/userfiles/files/18889466297.pdfIn PDF document text
    • http://gz-chengeng.com/uploadfile/files/59177198907.pdfIn PDF document text
    • http://synerfreight.com/syner_upload/images/files/86388169187.pdfIn PDF document text
    • https://aradovan.com/userfiles/file/zigibamaf.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BvfzZFkJO3s/uplcv?utm_term=tachycardia+resting+heart+ratePDF 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_off0000b1a0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB1A0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000c9b7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC9B7 10560 bytes
SHA-256: dcd9106fae33133d7aedb1115f08e7ee061d87cfab4c515cc43482a46dfff30b
font_02_sfnt_off0000e197.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE197 15264 bytes
SHA-256: cb66c927903789a95edc5d705185441fee70c0b9f67bb421843ae89c5fde4f45