Malicious PDF — malware analysis report

Static analysis result for SHA-256 90b1f9d55ff32a9a…

MALICIOUS

PDF

80.6 KB Created: 2021-09-11 17:04:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: a4e4a16aeed88c55b23a2d3a5e9acc5c SHA-1: 54d22342b953265a936ca09bff7639e0294721ba SHA-256: 90b1f9d55ff32a9ab60110c28c5a2de7203b59b1781bc63a2b24c8f202ce7ca0
156 Risk Score

Malware Insights

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

The PDF was flagged by a machine learning classifier and ClamAV as malicious, with heuristics indicating it functions as a link farm. Several extracted URLs point to compromised or disposable hosting, suggesting a phishing or malware distribution scheme. The presence of numerous external links, including those on compromised CMS uploads, strongly indicates an attempt to redirect users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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 https://dbjadow.pl/attachments/file/pevoz.pdf In PDF document text
    • http://ontis.sk/editor_uploads/system/files/pubevewejipebalozub.pdfIn PDF document text
    • http://nwatchonline.net/userfiles/file/zufalazitet.pdfIn PDF document text
    • http://gzcil.com/uploadfile/files/52174515702.pdfIn PDF document text
    • http://ghalemdi.com/userfiles/file/80005524807.pdfIn PDF document text
    • https://akdenizokullari.k12.tr/wp-content/plugins/super-forms/uploads/php/files/6g36mpubhd1btt15jrs7a5kr89/93789347033.pdfIn PDF document text
    • https://bank-kredit.at/ckfinder/userfiles/files/38488064732.pdfIn PDF document text
    • http://yearbookplus.com/uploads/ckfinder/files/kurabupisi.pdfIn PDF document text
    • https://argumentua.com/i/file/nimajoweviruviroxab.pdfIn PDF document text
    • http://hoangminhceramics.com/app/webroot/uploads/files/180506731.pdfIn PDF document text
    • https://vico-immobilien.com/ckfinder/userfiles/files/45421431445.pdfIn PDF document text
    • https://skyzoan.com/cake/beta/userfiles/file/93627247439.pdfIn PDF document text
    • http://fuhua.tumujike.com/assets/upload/files/202109011451153226.pdfIn PDF document text
    • http://akinmedical.com/uploads/file/58888131775.pdfIn PDF document text
    • http://vkts.se/userfiles/file/99437050498.pdfIn PDF document text
    • http://cyklo-sport-servis.cz/UserFiles/File/pekebexefixosibadaligebo.pdfIn PDF document text
    • http://vdadanang.vn/app/webroot/assets/files/gejawuziwifotamip.pdfIn PDF document text
    • https://mountainbrookbuilders.com/home/mountain/public_html/ckfinder/userfiles/files/vewew.pdfIn PDF document text
    • https://fleuriste79.fr/ckfinder/userfiles/files/kuranugubozigetasebuxuvid.pdfIn PDF document text
    • http://viettelhaiphong.me/data/dulieu/files/14057148516.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/161382f8d1b0d0---22514302761.pdfIn PDF document text
    • https://reklama71.ru/upload_picture/3955502689.pdfIn PDF document text
    • https://www.ciabrini-immobilier.com/wp-content/plugins/super-forms/uploads/php/files/liv6jfo02u6qse11p2tkf94f4p/fenedizejebilito.pdfIn PDF document text
    • https://espritgt.com/userfiles/file/27660237007.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/FevRqgeaUVY/uplcv?utm_term=what+happens+if+you+tip+a+fridge+on+its+sidePDF 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_off0000d565.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD565 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ed77.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED77 17864 bytes
SHA-256: 43f07d54ca42e3873c722258335fc4c99194d6ba29d14745a503523947545552
font_02_sfnt_off00011b76.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11B76 10940 bytes
SHA-256: e3005d56b9771a4ff2c8a9ac2603c0349b28dd9db468a87333dd1e959b8f5fa1