Malicious PDF — malware analysis report

Static analysis result for SHA-256 b13985482f06f7e0…

MALICIOUS

PDF

80.5 KB Created: 2021-09-17 20:36:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 5caabede584541ccd76297636bbfd65a SHA-1: f8c44022048ea33f86e46703a183ccb329c121de SHA-256: b13985482f06f7e0b34c3394a09798f39a3d9ee66941db7d4e58689d0835c24d
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains embedded JavaScript and multiple external URIs, many of which are part of a link farm pointing to disposable hosting or compromised CMS uploads. The ML classifier and ClamAV detection strongly indicate malicious intent, likely to redirect users to phishing or malware distribution sites. The embedded JavaScript is a common method for initiating malicious actions within PDFs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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 https://nomylo.ru/uplcv?utm_term=descargar+super+mario+bros+2+para+android+apk PDF link annotation
    • http://weldingplaza.com/files/file/12264950457.pdfIn PDF document text
    • http://servmed.net/userfiles/file/bikoxizepunumujavatudo.pdfIn PDF document text
    • http://gapp.fr/medias/files/20171785132.pdfIn PDF document text
    • http://xn--80aguejfegacgj0ad.xn--p1ai/pict/file/juvogavakujopuruji.pdfIn PDF document text
    • https://suhrsmad.dk/wp-content/plugins/formcraft/file-upload/server/content/files/1613c5bcd239cc---56953374588.pdfIn PDF document text
    • https://bozoklar.org/ckfinder/userfiles/files/dixulolenajajejir.pdfIn PDF document text
    • http://dydlhx.com/upfiles/file///sawefivakokujijibero.pdfIn PDF document text
    • http://ithalattagarantibelgesi.com/resimlerfiles/gufarapeborerumasik.pdfIn PDF document text
    • https://aartipalette.com/userfiles/file/baramasod.pdfIn PDF document text
    • http://wenfengsi.com/wfs/WebFiles/file///2021090303190868.pdfIn PDF document text
    • http://global-leasing-management.com/uf/file/25432339652.pdfIn PDF document text
    • https://zoomkish.com/basefile/zoomkishcom/files/2983220817.pdfIn PDF document text
    • https://amezdigital.com/wp-content/plugins/super-forms/uploads/php/files/40c301d90bd16dc71b5bc023937c2c99/daxusujozanomanokozom.pdfIn PDF document text
    • https://hanomanberjaya.com/contents/files/belojigufuxo.pdfIn PDF document text
    • http://paintmaster.hu/js/ckfinder/userfiles/files/94126396587.pdfIn PDF document text
    • http://quickfix-poland.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613ce50bd1a4d---jazofaxipesem.pdfIn PDF document text
    • https://saigonservices.vn/images/uploads/files/47769184100.pdfIn PDF document text
    • http://maimungkorn.com/UserFiles/file/sifamogober.pdfIn PDF document text
    • https://icrs-as.com/userfiles/file/namijalagokelurexikebixej.pdfIn PDF document text
    • http://abnicum.com/files/file/kowaxagovala.pdfIn PDF document text
    • http://kkagro.com/media/images/upload/file/43414503081.pdfIn PDF document text
    • http://siamsnail.com/media/userfiles/files/vegubup.pdfIn PDF document text
    • http://la-roofers.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16142d7af4be97---69565377910.pdfIn PDF document text
    • http://kimwendelldesign.com/ckfinder/userfiles/files/geranitoroxetumasuge.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_off0000d058.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD058 11164 bytes
SHA-256: 3f5d8b942b05147e6ae0949d7dfad30716de12af7c3b53a053c7404fa6b32490
font_01_sfnt_off0000ea13.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA13 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010225.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10225 19236 bytes
SHA-256: c26fdd70b72b47adb74e24fec2d54b403e681dd706318723eb44f67d7cacbfe3