Malicious PDF — malware analysis report

Static analysis result for SHA-256 5b13a611b4fb86a7…

MALICIOUS

PDF

73.3 KB Created: 2021-09-21 09:28:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 6de261496ecc06ccd2bc1199c1b806b5 SHA-1: 9a71fa951be69b6ca412f24d0eab5abe7457a86a SHA-256: 5b13a611b4fb86a7a4c6d509bbb646f3487b83216c05c224a37edca85cafb99d
156 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs that point to compromised websites and disposable hosting, indicating a link farm designed to redirect users to malicious content. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' strongly suggests this is a tactic for SEO poisoning or distributing malware via seemingly legitimate but compromised sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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://crewmak.ru/uplcv?utm_term=how+to+transfer+photos+from+phone+to+pc+wirelessly PDF link annotation
    • https://mosoptagro.ru/wp-content/plugins/super-forms/uploads/php/files/bb1c780789fe96d551b813260a9668b9/72298267799.pdfIn PDF document text
    • https://hockeymro.ca/docs/file/majimezafojawebibad.pdfIn PDF document text
    • https://klcmekatronik.com/ckfinder/userfiles/files/worekis.pdfIn PDF document text
    • http://boxshop.mn/userfiles/files/72045208724.pdfIn PDF document text
    • https://www.kiakaha.gr/wp-content/plugins/super-forms/uploads/php/files/5nv8lh50rvml1p6fojd1o7s34n/88625420910.pdfIn PDF document text
    • https://chingchia.com/uploads/files/202109191027457463.pdfIn PDF document text
    • http://amghanoi.com/images/ckeditor/files/ludulozugel.pdfIn PDF document text
    • http://kepco-group.com/uploaded_files/userfiles/files/71129090858.pdfIn PDF document text
    • https://fivetc.net/uploads/files/39907551289.pdfIn PDF document text
    • http://kmjmt.com/news/upload/file/210912173414332712f6zk8x.pdfIn PDF document text
    • http://thanhnienxp.com/vietkiendo/upload/file/libuwunuvuf.pdfIn PDF document text
    • http://andreuma.madteam.net/ckfinder/userfiles/files/92159230286.pdfIn PDF document text
    • https://sklepbonus.pl/userfiles/file/fefoluxuroxovel.pdfIn PDF document text
    • https://guineaservicesproviders.com/gsp/files/xiwavemukabo.pdfIn PDF document text
    • http://paymentsbusiness.ca/wp-content/plugins/formcraft/file-upload/server/content/files/161365e323ea02---67800267251.pdfIn PDF document text
    • http://enjoy.sk/editor_uploads/system/files/53504827533.pdfIn PDF document text
    • https://isagrinio.gr/userfiles/jolafakowonupajesoneb.pdfIn PDF document text
    • https://palezieux.com/ckfinder/userfiles/files/jafedepupurirojukira.pdfIn PDF document text
    • http://garmaclima.com/uploads/ckfinder/files/wifufapom.pdfIn PDF document text
    • http://www.arborvitae.cz/ckfinder/userfiles/files/mabijafi.pdfIn PDF document text
    • http://veewood.com/file_media/file_image/file/xajefolomexelikinezim.pdfIn PDF document text
    • https://profm.hu/files/file/gideviwiponomewox.pdfIn PDF document text
    • http://signauction.net/userfiles/file/punubuwila.pdfIn PDF document text
    • https://altonika.pro/files/fck/file/57267597885.pdfIn PDF document text
    • 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_off0000bc8c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBC8C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d4a3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD4A3 10936 bytes
SHA-256: b0e81640513d11edf164102803e2ee1add93063ac789b6bb2d34b1b09743f4b7
font_02_sfnt_off0000edd1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEDD1 15900 bytes
SHA-256: 54628a993605eb24878ee4dfea22ee84a49461f32a4a96680713ec21650a1f0d