Malicious PDF — malware analysis report

Static analysis result for SHA-256 8c4055ce3da39e37…

MALICIOUS

PDF

79.5 KB Created: 2021-09-08 17:19:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 1f4b3f8fef8f78d5ee0c5783ccff3fc6 SHA-1: 825089244843e3b5661585618fbbc041797b8118 SHA-256: 8c4055ce3da39e37198b3d747d28d4d9b74400a9e53a1724fa9690484f76decb
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains multiple links to external websites, with several heuristics indicating it functions as a link farm hosted on potentially compromised or disposable domains. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or distributing further malware. Although no scripts were explicitly extracted, the PDF structure and embedded URIs point towards an attempt to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9968

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 http://www.caribbeandentist.com/wp-content/plugins/formcraft/file-upload/server/content/files/16135913509823---79925808047.pdf In PDF document text
    • http://karate-talence.com/newsite/userfiles/files/fusibane.pdfIn PDF document text
    • https://suadienlanhhanoi.net/upload/files/dugolegomojomevo.pdfIn PDF document text
    • http://petrduchek.com/files/10775689083.pdfIn PDF document text
    • http://thrifty-uy.com/files/others/susajewavopi.pdfIn PDF document text
    • http://www.cda.org.hk/ckfinder/userfiles/files/midovobigefi.pdfIn PDF document text
    • https://www.indee-r.fr/wp-content/plugins/super-forms/uploads/php/files/f18bcadfeaa2e77767528b91d3bf8ed1/bekivusimukujes.pdfIn PDF document text
    • http://giadinhmedia.com/uploads/files/sugex.pdfIn PDF document text
    • http://fundacjahfg.pl/upload/file/60010361285.pdfIn PDF document text
    • http://conservationenergy.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f87588e011---31763057700.pdfIn PDF document text
    • http://quetthe.com/upload/files/92058921203.pdfIn PDF document text
    • http://twgo8.com/uploads/base/files/202109031348407709.pdfIn PDF document text
    • http://goldenmallbiotech.com/upload/files/tumap.pdfIn PDF document text
    • http://indianspringhomes.net/userfiles/files/35914298715.pdfIn PDF document text
    • https://wisestudentz.com/userfiles/file/jifurogivibowud.pdfIn PDF document text
    • http://stroykap.com/application/views/stroykap/userfiles/file/rivumekezawupekiwemi.pdfIn PDF document text
    • http://vnationwide.com/userfiles/files/zeruvuxapadiwuwebexani.pdfIn PDF document text
    • http://www.coverseg.com/uploads/ckfinder/files/diletinon.pdfIn PDF document text
    • http://omeofest.eu/userfiles/files/46021569085.pdfIn PDF document text
    • https://siahotel.com/userfiles/files/5606927665.pdfIn PDF document text
    • http://skonasystems.com/userfiles/file/89708634431.pdfIn PDF document text
    • https://fotobolfestmeny.hu/mvc/userfiles/file/zadof.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/fzgW7-mxBc0/uplcv?utm_term=physics+worksheet+lesson+5+two+dimensional+motion+and+vectors+answersPDF 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_off0000cf05.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCF05 17920 bytes
SHA-256: e520998c4821aa8ee70bd1ea4ed6ec8a65bad6fdb445181c8ccc88ca202d8238
font_01_sfnt_off0000fde7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFDE7 11128 bytes
SHA-256: 1274475b1d123f1153a489578d6d40faba5bd44056a0eec3fa3d2485b4748af5
font_02_sfnt_off000117d8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x117D8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1