Malicious PDF — malware analysis report

Static analysis result for SHA-256 5db91fee1d8dea41…

MALICIOUS

PDF

86.2 KB Created: 2021-07-04 07:35:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-14
MD5: ca3e53b1122242265c2c9b3ec347a07a SHA-1: b23704e83e1c0ee0bb424722ef313884b9d7754c SHA-256: 5db91fee1d8dea41b8c6c066a89a6013d1508047a0563609d4ec0541a3471735
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was flagged by multiple heuristics as malicious, including a high-confidence ML classifier and ClamAV detection as a phishing trojan. It contains numerous embedded URLs that point to compromised WordPress sites and other disposable hosting, suggesting a link farm designed to redirect users to malicious content. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, indicating it's not intended for human readability but rather as a vehicle for these malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

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://ketchas.ru/uplcv?utm_term=how+fast+can+a+great+white+shark+swim+in+mph PDF link annotation
    • https://adiwirawanbali.com/wp-content/plugins/super-forms/uploads/php/files/23e7d9c51ad32dbf6293001870e57a5e/momivakakujiki.pdfIn PDF document text
    • http://mosjob.ru/images/file/medulediredoxomunada.pdfIn PDF document text
    • https://evpersoneli.net/ev-personeli/file/dowazuzudumomewaxalexa.pdfIn PDF document text
    • https://gresathouse.com/wp-content/plugins/super-forms/uploads/php/files/5af7143724abc3dd3f20aa2e7f5b9051/7816113203.pdfIn PDF document text
    • http://lamgi.pl/ckfinder/userfiles/files/26603376193.pdfIn PDF document text
    • http://emirates-offshore.com/uploads/image/file/fivajuximitevekonezurigi.pdfIn PDF document text
    • http://www.unidacardoso.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1609bfa65e433d---weraduzefarezibepidawu.pdfIn PDF document text
    • https://elicopter-de-inchiriat.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160788ff67426e---20818360386.pdfIn PDF document text
    • https://sevsport.info/wp-content/plugins/super-forms/uploads/php/files/a1950ccba5bc08e91f545ce3f333ce54/jukoxivupujor.pdfIn PDF document text
    • https://bokseinstituttet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/160c895100449a---51965355681.pdfIn PDF document text
    • http://www.julitolaschools.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d9cf1818f80---tavudobagabapus.pdfIn PDF document text
    • http://christembassydocklands.org/wp-content/plugins/super-forms/uploads/php/files/5e3039702e8264e7b03d8796bdcbcdda/dizudijilirimoxofarikev.pdfIn PDF document text
    • https://drsubhashawale.com/ckfinder/userfiles/files/72185467214.pdfIn PDF document text
    • http://libron.pl/fckupload/assets/file/dagagizumiziluzekuwaxov.pdfIn PDF document text
    • http://goldway.jp/upload/board/file/34824614340.pdfIn PDF document text
    • https://freedomtampons.com/wp-content/plugins/super-forms/uploads/php/files/647c409b4b8921ecbed4b16c9d289466/64676071319.pdfIn PDF document text
    • https://allcreaturesinc.com/files/files/kirejulasawujaxiso.pdfIn PDF document text
    • http://whs1979.net/clients/65916/File/dakijawodefolitipumas.pdfIn PDF document text
    • http://files.ibiza-ferien.de/file/62381317486.pdfIn PDF document text
    • http://agendatourvietnam.com/hinhanh/file/bejakidijonen.pdfIn PDF document text
    • https://rebel-guitars.com/wp-content/plugins/super-forms/uploads/php/files/52d9ff61207f966570df06cf432c3825/jasaganujo.pdfIn PDF document text
    • http://www.kevinbrooks.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1607acac082520---sakodipikijepijuzizori.pdfIn PDF document text
    • http://cainghienbinhduong.com/uploads/userfiles/file/57919514850.pdfIn PDF document text
    • http://sarahscupcakery.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609d330a0fbc4---23909248419.pdfIn PDF document text
    • https://www.energetisch-therapeut-estie.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1607e4c19c4740---5818473662.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_off0000eccf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xECCF 11048 bytes
SHA-256: 818083ce65731e4ed84e57d119c281c476719a01c5c25a55bbb66b5151269e33
font_01_sfnt_off00010663.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10663 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011e75.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E75 17128 bytes
SHA-256: 2de7797d08550c161fe28341225921b87b8fc16b4c92194f60341d001d06bbe3