Malicious PDF — malware analysis report

Static analysis result for SHA-256 5b234b837b19e1b1…

MALICIOUS

PDF

78.5 KB Created: 2021-09-09 20:07:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 0b0aaba8cd998c967b6c98f23a2d9167 SHA-1: 63f224c47752bacd673fff3c15e990c412903e11 SHA-256: 5b234b837b19e1b1b8793c901b899703ea71c4b9d943ad5b458ce2359113e167
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected as malicious by ClamAV and an ML classifier, and exhibits characteristics of a link farm on disposable hosting. Multiple heuristics indicate the PDF contains external links to algorithmically-generated URLs, suggesting a phishing or malware distribution attempt. The presence of embedded URLs and the nature of the heuristics strongly suggest the PDF's primary function is to redirect users to malicious external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9944

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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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=logan+2017+stream PDF link annotation
    • https://sts-cct.com/app/webroot/userfiles/files/76673020047.pdfIn PDF document text
    • http://luckdidea.com/ckfinder/images_store/files/famujufobim.pdfIn PDF document text
    • https://ekoelprom.pl/public/images/editor/file/kokuwo.pdfIn PDF document text
    • http://ufcnagykanizsa.hu/userfiles/file/gudusakominup.pdfIn PDF document text
    • http://nhagiatxanh.com/public/default/ckeditor/files/botamubopazakekasava.pdfIn PDF document text
    • http://grapes4u.ca/sites/all/sites/grapes4u.ca/files/85200265813.pdfIn PDF document text
    • http://evabody.ro/wp-content/plugins/formcraft/file-upload/server/content/files/161350e63cbb65---69618584014.pdfIn PDF document text
    • http://gearcon-eng.com/file_media/file_image/file/zitudibupefojuvu.pdfIn PDF document text
    • https://stthomasorthodoxchurchsouthpampady.com/userfiles/file/damige.pdfIn PDF document text
    • https://farmacieitaliane.com/documenti/file/90778941787.pdfIn PDF document text
    • http://driscollandgibson.com/images/edit_images/file/guronogewemigojavisixik.pdfIn PDF document text
    • http://rewitex.pl/userfiles/file/resodozifimunevuvisuve.pdfIn PDF document text
    • http://vilocom.net/webroot/img/files/9851097967.pdfIn PDF document text
    • http://fabiocaronearchitetto.com/userfiles/files/zidazokuranubakulipufive.pdfIn PDF document text
    • https://stpetejazz.com/wp-content/plugins/super-forms/uploads/php/files/4i7tbftov11vb4u72g45ob65g2/31311844995.pdfIn PDF document text
    • http://www.deep2001.com/images/library/File/varapuviwolomadufolut.pdfIn PDF document text
    • http://xn--ob0bjxt9h99icicrvkksa421cwwp7hiv4d6a.com/ckfinder/userfiles/files/mezegotududuvikunamavi.pdfIn PDF document text
    • http://kripasec.com/userfiles/file/22744419174.pdfIn PDF document text
    • http://delta-serwis.pl/pliki/15293138760.pdfIn PDF document text
    • https://3drm.bg/uploads/pictures/files/71799005754.pdfIn PDF document text
    • http://ottotech.center/userfiles/file/vowitapubaxix.pdfIn PDF document text
    • https://taiwancy.com/app/webroot/userfiles/files/88197808768.pdfIn PDF document text
    • http://scard.vn/app/webroot/uploads/files/jexewixanizijavidepuj.pdfIn PDF document text
    • http://bukvoznaika.ru/ckfinder/userfiles/files/limirulidoza.pdfIn PDF document text
    • http://suchanekstomatolog.pl/files/file/suwuzuxekupima.pdfIn PDF document text
    • http://manpukulivermore.com/uploads/files/rewegupiliwo.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_off0000cd65.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCD65 17840 bytes
SHA-256: c1c0aaec0e9d9546bf8f7fa6a37b5fd078b5d41042a15a58f340cb46d8432b2e
font_01_sfnt_off0000fbdb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFBDB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000113f2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x113F2 10616 bytes
SHA-256: e528716d0717fe22556df92e954834d4735796ab625949a97f27662c43c69b0b