Malicious PDF — malware analysis report

Static analysis result for SHA-256 91ab05a728db787e…

MALICIOUS

PDF

80.8 KB Created: 2021-09-10 02:48:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: a9631e6ca96743b013b2600bf8c2c5c8 SHA-1: 5f9e40c8dc805ee176ef0593cccf9cb82a577589 SHA-256: 91ab05a728db787effe419cfea29acd2db63855eae9f8758ca20122880509365
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF was flagged by ML classifiers and ClamAV as malicious, indicating a phishing or trojan payload. It contains numerous embedded URLs pointing to a link farm hosted on disposable domains, a common tactic for distributing malicious content or conducting phishing campaigns. The presence of PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, suggesting the PDF is designed to appear legitimate through link density while using deceptive hosting.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9949

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://oazapiekna.com/zdjecia/fck/file/sevanepefobe.pdf In PDF document text
    • http://www.c-l-r-p.com/admin/ckfinder/userfiles/files/zuxarekisibukixedak.pdfIn PDF document text
    • http://bouwbedrijfansing.nl/userfiles/file/84645188724.pdfIn PDF document text
    • http://hanmih.com/userfiles/file/20210907023556.pdfIn PDF document text
    • http://arunimaflavours.com/userfiles/file/98768210161.pdfIn PDF document text
    • http://pet.nfe.go.th/m_site/ckfinder/userfiles/files/kaviguzamigokagox.pdfIn PDF document text
    • https://abss.pt/userfiles/file/14085336664.pdfIn PDF document text
    • http://bagpack.com.np/wp-content/plugins/formcraft/file-upload/server/content/files/1613a091b95c0b---24190826010.pdfIn PDF document text
    • http://materialdeestudo.top/userfiles/files/xomibilud.pdfIn PDF document text
    • http://gintaras.cz/userfiles/file/71842231578.pdfIn PDF document text
    • http://mwcapital.net/ckfinder/userfiles/files/96564741862.pdfIn PDF document text
    • http://suchanekstomatolog.pl/files/file/67822421685.pdfIn PDF document text
    • http://balashixa.inhome360.ru/admin/ckfinder/userfiles/files/pazizomafe.pdfIn PDF document text
    • http://dunajecbiala.pl/upload/File/24693156784.pdfIn PDF document text
    • http://studiomistretta.com/userfiles/files/buzoxeb.pdfIn PDF document text
    • http://7profi.net/userfiles/file/17521277313.pdfIn PDF document text
    • http://aktien-analyse.de/images/File/42972399669.pdfIn PDF document text
    • http://www.megasaludips.com/wp-content/plugins/formcraft/file-upload/server/content/files/161320bfe29a7e---97357353193.pdfIn PDF document text
    • http://www.barbazan-debat.fr/ckfinder/userfiles/files/3704907131.pdfIn PDF document text
    • https://resulgame.com/calisma2/files/uploads/notesalitojedovu.pdfIn PDF document text
    • http://plenaseguroseprevidencia.com/fotosempresa/files/36573178100.pdfIn PDF document text
    • http://leaders-adv.net/userfiles/file/7401765740.pdfIn PDF document text
    • https://printjet.pl/pliki_user/File/xupuveliwuz.pdfIn PDF document text
    • https://hgb.se/filer/file/negogisibalar.pdfIn PDF document text
    • http://toanthinh.vn/webroot/img/files/wipadevulanu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/zMnd8XtcwSM/uplcv?utm_term=wifi+hacker+mod+appPDF 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_off0000d8ac.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD8AC 17680 bytes
SHA-256: 0616d0667dbcc5c4c5e42e7d0b9a33550c48269496df4549243283f26e6cbf47
font_01_sfnt_off0001061f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1061F 10552 bytes
SHA-256: c3d81d09d0f562e0e508330163d2f66fbe8d33f4cfa456aaefe069c2aa3afa8f
font_02_sfnt_off00011e2a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E2A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1