Malicious PDF — malware analysis report

Static analysis result for SHA-256 cbf9ce0356021a2e…

MALICIOUS

PDF

82.2 KB Created: 2021-09-19 03:53:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: c7e8ea1d424146cd4e60cb33bfe258d5 SHA-1: 09e365b379b298413b42b1522d6430969f1f581f SHA-256: cbf9ce0356021a2e0cb353f4572ba4d2dc9832b961a239c637319d21125a1f24
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF containing embedded JavaScript and a significant number of external URIs. Several heuristics indicate that the PDF is a link farm, with some links pointing to compromised CMS upload storage and others hosted on disposable domains. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or SEO poisoning to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9846

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://arsvet.ru/img/upload/wakuban.pdf
    • https://gameclub.by/uploads/files/82799429145.pdf
    • https://subarini.ro/mm/file/15888100375.pdf
    • https://silatur.com/js/ckfinder/userfiles/files/63381336819.pdf
    • https://webornate.com/viking1/uploads/files/97044484430.pdf
    • http://stonestudio.pl/files/upload/file/rajim.pdf
    • http://rkenterprisesonline.com/FCKeditor/file/78430702779.pdf
    • https://dcoderesearch.com/uploads/54083358866.pdf
    • https://octvads.site/js/ckfinder/userfiles/files/vekaligidoxena.pdf
    • http://platypusspot.org/uploads/ckfinder/userfiles/files/sugofevuwuvixonuzenikofi.pdf
    • http://joyearland.com/ckfinder/userfiles/files/45233541703.pdf
    • http://ambulatorioveterinarioilprato.eu/userfiles/files/33806587809.pdf
    • http://awkontrakt.pl/ckfinder/userfiles/files/lizirusadomeleruzepik.pdf
    • http://bsinteriordesigner.com/userfiles/files/61249674521.pdf
    • http://boonfagrandhome.com/user_img/files/80110686717.pdf
    • http://myucmas.com/userfiles/file/xogefudozow.pdf
    • http://karaokejdi.com/ckfinder/core/connector/php/upload/files/56775421920.pdf
    • http://anpharma.net/upload/files/17328860228.pdf
    • https://www.burit.net/wp-content/plugins/formcraft/file-upload/server/content/files/16144670838fb2---61975623634.pdf
    • http://brodart01.com/wp-content/plugins/super-forms/uploads/php/files/akq7g1uvl1maqdqhu7ka0ki7ik/favofenisovurapopor.pdf
    • http://english-island.pl/wp-content/plugins/super-forms/uploads/php/files/37vgi8mven4ec5u8up17urt7e7/dulefonuworimitido.pdf
    • http://uts.edu.co/portal/app/ckfinder/userfiles/files/78251316412.pdf
    • https://alice-immo.com/userfiles/file/97347565506.pdf
    • https://demo.wsbe17hongkong.hk/_bin/ckfinder/userfiles/files/12016568078.pdf
    • https://gberwanda.com/gbe/useruploads/blogs/files/49078831104.pdf
    • http://www.urbanwaterways.info/files/babeniburokajesanosex.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=material+design+meaning
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000dc83.bin
f8167bb55fd6449eec3aaf8cda9b1719245a768af58821e2dac18daad06afb34
pdf-font-stream PDF embedded font (sfnt) at offset 0xDC83 10464 bytes
font_01_sfnt_off0000f401.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF401 16792 bytes
font_02_sfnt_off00010c13.bin
097dea28497c9ebbb772e2c365ff366aac9a308b52fb4be33e2e7f86475f9d62
pdf-font-stream PDF embedded font (sfnt) at offset 0x10C13 17864 bytes