Malicious PDF — malware analysis report

Static analysis result for SHA-256 391d630fdff9418c…

MALICIOUS

PDF

80.5 KB Created: 2021-09-10 02:17:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: ac7ac5312b8501d5e9196ffd2bc6720c SHA-1: eb0c8ef49fe742ca6d6405d465f4562c10672457 SHA-256: 391d630fdff9418c4ff69d5ae64993b15a3ac590f6bfb60d9e404236a95291b8
156 Risk Score

Malware Insights

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

The PDF contains numerous external links, with several heuristics indicating it functions as a link farm. Notably, some links point to compromised WordPress upload directories, suggesting a potential distribution point for further malicious content. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware distribution via these external links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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://quick-thailand.com/images/uploads/file/9000117731.pdf In PDF document text
    • https://duocvinhkim.com/userfiles/file/kulokoliwobo.pdfIn PDF document text
    • http://gearcon-eng.com/file_media/file_image/file/77077548794.pdfIn PDF document text
    • http://blueview.nl/app/webroot/files/userfiles/files/lizebakapakizetilesem.pdfIn PDF document text
    • http://inwallendorf.de/userfiles/file/weronebipadoxavil.pdfIn PDF document text
    • http://watch62.ru/files/files/bulemaxonirez.pdfIn PDF document text
    • http://e-photo.lv/ckfinder/userfiles/files/11077244378.pdfIn PDF document text
    • http://www.pirac.org/wp-content/plugins/super-forms/uploads/php/files/7e181f77fbcd961346f843085472247f/55366866586.pdfIn PDF document text
    • http://slstudio.it/userfiles/files/7918446460.pdfIn PDF document text
    • https://gaseg.com/wp-content/plugins/super-forms/uploads/php/files/7s2756tiqs2ui99h49u5jltdbg/34444897321.pdfIn PDF document text
    • https://mytalk7.com/_UploadFile/Images/file/bikovi.pdfIn PDF document text
    • http://timnhanhonline.vn/upload/files/fodiwoxo.pdfIn PDF document text
    • http://melissajacksonmd.com/wp-content/plugins/formcraft/file-upload/server/content/files/161376532ef98d---nusamilipewisoxalujuf.pdfIn PDF document text
    • http://kindergartenhelden.at/upload/file/30232786667.pdfIn PDF document text
    • http://kirilmazbardak.com/userfiles/file/wikudu.pdfIn PDF document text
    • https://rimi.sk/userfiles/file/40872018577.pdfIn PDF document text
    • https://siphouse96.com/wp-content/plugins/super-forms/uploads/php/files/ec62d87c592741b182ff68ce7a7b2d86/7095557837.pdfIn PDF document text
    • http://www.astmalek.cz/obrazky/file/34297254191.pdfIn PDF document text
    • https://lazdynumokykla.lt/userfiles/file/tonarebotemitiridalipobid.pdfIn PDF document text
    • http://beta-rc.com/upload/files/57186418439.pdfIn PDF document text
    • https://vanrun-it.nl/userfiles/files/66820131534.pdfIn PDF document text
    • https://mai-avto.ru/upload_files/file/budovovunusali.pdfIn PDF document text
    • https://realwebguys.com/wp-content/plugins/formcraft/file-upload/server/content/files/161367e9f3d3e7---64856981090.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=words+that+start+with+marPDF 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_off0000d836.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD836 17168 bytes
SHA-256: 215fb2663e579269151b75416eec358b5efb2144fa4326c85827d2afe5c70cee
font_01_sfnt_off000104ea.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x104EA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011d01.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11D01 10308 bytes
SHA-256: 70f7063951f825b358d5749da13cade8560ad4de73ed3b191ae4abbabca22a5f