Malicious PDF — malware analysis report

Static analysis result for SHA-256 f53a14d51a1af952…

MALICIOUS

PDF

131.0 KB Created: 2021-09-11 22:18:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: c856ad190fe51ee4851fc656fa92de74 SHA-1: 22ad144ded7cf9d5f29b4889a0e14f56fdfa6287 SHA-256: f53a14d51a1af9520f667c1509c9104235963b0dcd6d34d7d29149ffcf5b4c98
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF containing an embedded JavaScript stream and a link farm pointing to various PDF files hosted on potentially compromised or disposable domains. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The presence of JavaScript suggests an attempt to execute malicious code within the PDF viewer.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9963

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://pnc21.com/files/fckeditor/file/126131671461310dc824022.pdf
    • https://penzionradvanice.cz/res/file/midelus.pdf
    • http://a1-automotivegroup.com/upload/files/gezefekomakofabokuzon.pdf
    • https://www.kiteschule-kiel.de/wp-content/plugins/formcraft/file-upload/server/content/files/16138eb1e6b47c---kulijuwisumobunujabune.pdf
    • https://www.scanworld.se/wp-content/plugins/formcraft/file-upload/server/content/files/16139921bc15ec---95864068463.pdf
    • https://beytarimcilik.com/admin/editor_resim/file/66943038685.pdf
    • https://mahae.hu/files/files/58108830989.pdf
    • http://hicoweld.com/shop/fck_file/file/22054394120.pdf
    • http://jiji.pgo.tw/pic/uploads/files/sepodizebavepakize.pdf
    • http://27derajat.com/assets/ckfinder/core/connector/php/uploads/files/norunetu.pdf
    • http://autosvanbeek.nl/mindcms/js/ckf/userfiles/files/famajofufikopigoxudopi.pdf
    • http://yuh-tarng.com/userfiles/file/gemugutaxeranazaz.pdf
    • http://flamefitnessstudio.com/cewit/images/file/14426364325.pdf
    • http://mrcookie.tw/upload/editor/file/02135557400.pdf
    • http://urs-certification.com/gais/image/file/74757686651.pdf
    • https://aneri12.cz/res/file/76392583064.pdf
    • http://homeopathyhongkong.org/files/nefebixaxijawekakawon.pdf
    • https://mosoptagro.ru/wp-content/plugins/super-forms/uploads/php/files/949a78e4d1f61019f489572465c7afc4/68640144699.pdf
    • https://www.marbelitesa.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/1612fbea91f783---tapude.pdf
    • http://sdds.be/userfiles/file/89534357550.pdf
    • https://gemwares.com/userfiles/file/libudowatavuwikewi.pdf
    • http://kastely-vacduka.hu/fileok/file/38969323012.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/LPIa9PGmDLg/uplcv?utm_term=minna+chuukyuu+1+pdf
    • 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_off00018d8c.bin
5412ef414ae3f55022eac77bb5dd9114b8fa2639491adbec2ebe51ef05951de0
pdf-font-stream PDF embedded font (sfnt) at offset 0x18D8C 10404 bytes
font_01_sfnt_off0001a510.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x1A510 16792 bytes
font_02_sfnt_off0001bd22.bin
397d9bba0f23712421b0c02fdf91ff2fc40cf412702d42bb3d3f51bd674eb6a0
pdf-font-stream PDF embedded font (sfnt) at offset 0x1BD22 25988 bytes