Malicious PDF — malware analysis report

Static analysis result for SHA-256 7b5bb3c03a362f15…

MALICIOUS

PDF

68.3 KB Created: 2021-09-29 11:38:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 99042acd4df8ac442149f84675cedd1e SHA-1: 686820f5d98a4d385a91b6ac2a140ca3653ecebe SHA-256: 7b5bb3c03a362f15b85cd18774e32150efe8d590e6a97a2cedfef6d26bf9c0cc
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains an embedded JavaScript stream and numerous URLs, many of which point to compromised CMS uploads or disposable hosting, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or malware distribution. The embedded JavaScript may be used to facilitate the redirection or exploit vulnerabilities.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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://zhongjiukeji.com/upload_fck/file/2021-9-23/20210923145119641252.pdf In PDF document text
    • http://idolyokocho.com/js/ckfinder/userfiles/files/ganalubedugela.pdfIn PDF document text
    • http://chono.mn/uploads/userfiles/files/gupujabi.pdfIn PDF document text
    • http://kythuatviet.vn/uploads/userfiles/file/simuxevoxuwe.pdfIn PDF document text
    • https://ms02bet.com/contents/files/nuwopurizosukotuvemato.pdfIn PDF document text
    • http://omgmediatank.com/userfiles/files/kosokego.pdfIn PDF document text
    • https://ce-mi.pl/uploads/userfiles/files/36144591124.pdfIn PDF document text
    • http://bytip.net/filespath/files/20210921065211.pdfIn PDF document text
    • https://peterdegendt.be/file/68320994692.pdfIn PDF document text
    • https://ccveg.org/wp-content/plugins/super-forms/uploads/php/files/hlmbfvpfe9enscgk2vm0canmo9/22830137709.pdfIn PDF document text
    • http://acupunctuuryao.nl/ckfinder/userfiles/files/wewopumewev.pdfIn PDF document text
    • https://mkserwis.pl/userfiles/file/24859011574.pdfIn PDF document text
    • http://kuhomania.ru/ckfinder/userfiles/files/savikibanekagixem.pdfIn PDF document text
    • https://flylights.pl/wp-content/plugins/super-forms/uploads/php/files/eibfo9b6qihjdlod4saulj73qn/dumoxetenutoko.pdfIn PDF document text
    • http://dieterheich.de/images/uploads/file/39075990217.pdfIn PDF document text
    • http://meteosputnik.ru/userfiles/file/bajifipimajiwar.pdfIn PDF document text
    • https://designmaster.in/scgtest/eec-new/codelibrary/ckeditor/ckfinder/userfiles/files/duseka.pdfIn PDF document text
    • https://phuketwebstudio.com/ckfinder/userfiles/files/80026457223.pdfIn PDF document text
    • http://guoyangmoju.com/userfiles/files/getomozakimen.pdfIn PDF document text
    • https://www.novet.de/wp-content/plugins/formcraft/file-upload/server/content/files/16138a06c58ce7---95885757432.pdfIn PDF document text
    • https://brokenspoke.com/wp-content/plugins/super-forms/uploads/php/files/629113537dcff21e6c2b8d31167450a2/3406909405.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/DOqCt-cVA4I/uplcv?utm_term=bloom%27s+taxonomy+summarizePDF 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_off0000ab76.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAB76 10732 bytes
SHA-256: 184b5eca487b33380383a5f7c00a02077db2c09af5b9b968c7250e06666686f5
font_01_sfnt_off0000c447.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC447 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000dc59.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC59 15068 bytes
SHA-256: c16833f4c3b77002e46b9e7534e987deabf6e6c4fe0836335ac94c3fa7a6bc50