Malicious PDF — malware analysis report

Static analysis result for SHA-256 0c91c3af7b6c1ca3…

MALICIOUS

PDF

94.3 KB Created: 2021-09-12 22:52:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 09c49e5bb169d34368073e76cb16707a SHA-1: 25f44eec36a8b19a64cfbcb15dda14d975059873 SHA-256: 0c91c3af7b6c1ca3aa42919a3815ac1db504abc2c12b93b17b446322aa88a8c4
156 Risk Score

Malware Insights

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

This PDF was flagged by multiple heuristics and an ML classifier as malicious, with ClamAV identifying it as a phishing trojan. It contains numerous links, many pointing to compromised CMS upload storage or disposable hosting, suggesting a link farm designed to redirect users. The document body is heavily obfuscated and unreadable, but the presence of external URIs and the link farm heuristics indicate a likely intent to redirect users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9969

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://hsse.hssanesteban.cl/files/7699985509.pdf In PDF document text
    • http://klubbelgickychobrov.sk/editor_uploads/files/49184585192.pdfIn PDF document text
    • http://www.miamiairportlimo.net/wp-content/plugins/formcraft/file-upload/server/content/files/16134adcf518d7---bewidirasibu.pdfIn PDF document text
    • http://houstontca.org/Content/uploads/files/logatet.pdfIn PDF document text
    • https://gdaniec.com/upload/files/momiwapibozogurojojapoge.pdfIn PDF document text
    • https://dermo.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138583249ec6---55536709011.pdfIn PDF document text
    • http://datong-travel.tw/upload/ckeditor/files/20210902151003.pdfIn PDF document text
    • https://leavereview.com/customerinterview/ckfinder/userfiles/files/93677466294.pdfIn PDF document text
    • http://erpos.sk/data/files/94869936797.pdfIn PDF document text
    • http://insfilings.com/skyzone_classic/upload/files/96890931142.pdfIn PDF document text
    • http://www.jindatunnel.com/up_files/file/witapagekasew.pdfIn PDF document text
    • https://mingyi-lock.com/data/file/userfiles/files/90779238010.pdfIn PDF document text
    • https://kalatranslation.co.uk/wp-content/plugins/super-forms/uploads/php/files/dj4gjcduk3a3irfqmo9fqcio61/59675628405.pdfIn PDF document text
    • http://iktoktatas.hu/files/file/19088470840.pdfIn PDF document text
    • http://austral-immo.com/userfiles/files/10688868780.pdfIn PDF document text
    • http://hingliltd.com/userfiles/vuxozopafolan.pdfIn PDF document text
    • https://nationalcardsolutions.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e2e2598819---nobanonifovawuvadupa.pdfIn PDF document text
    • http://a-b-i-s.net/layout/bilder/file/fitigezogezavajepuxu.pdfIn PDF document text
    • http://purofirstli.net/userfiles/file/30041536911.pdfIn PDF document text
    • https://sca-eagleegg5k.com/ckfinder/triplebuserfiles/file/84453169047.pdfIn PDF document text
    • https://dotcomtravelegypt.com/userfiles/files/puruvidavumonirajoveripa.pdfIn PDF document text
    • https://mystruggle.uk/indigo/ckfinder/userfiles/files/litapidimufa.pdfIn PDF document text
    • http://vuonlan.vn/data/upload/files/48774122603.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/fzgW7-mxBc0/uplcv?utm_term=mp3+juice+malayalamPDF 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_off00010ba5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10BA5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000123b7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x123B7 18568 bytes
SHA-256: f4971c4d5f9ac081bf64e93d69b58157de3a35b4baa96e023cd24045e5c72888
font_02_sfnt_off000153fa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x153FA 10456 bytes
SHA-256: 8f8a94ff47e139a408e155127c8b3db65024ca96f3daab6210766bc51351f371

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