Malicious PDF — malware analysis report

Static analysis result for SHA-256 91cab342491651fd…

MALICIOUS

PDF

80.8 KB Created: 2021-09-21 06:14:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 9737a7864121374baba3b3e54dcfd9a5 SHA-1: 60047158ac44d1eab9d411add6f0c7d2c383a2cb SHA-256: 91cab342491651fd0110354b28159f2e873282b05680344a37c4a55aa336547f
196 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, with heuristics indicating it is a link farm and a browser extension installation lure. The embedded URLs, while many are marked benign, suggest an attempt to redirect the user to malicious sites. The document body is heavily obfuscated and unreadable, preventing a deeper analysis of its specific content, but the overall pattern points to a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

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
  • Browser extension / update installation lure high SE_BROWSER_INSTALL_LURE
    Document tells the user to install a browser extension, plugin, viewer, or browser update to view content — a common social-engineering path for credential theft and malware installation
  • 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://brihat-group.com/assets/userfiles/files/70589059809.pdf
    • http://madonnina.info/userfiles/files/ruvoz.pdf
    • https://avukatwebsitesi.trakyasoft.com/upload/files/58489472774.pdf
    • http://zsdbiopharm.com/upload/files/wasibebeporukonipufu.pdf
    • https://kolorubursztynu.kolorubursztynu.pl/web/uploads/files/95937622254.pdf
    • http://cn-polylysine.com/d/files/batufusijalugosimeme.pdf
    • https://skvely-kup.cz/files/file/zazukozubevinemov.pdf
    • https://www.peeryhotel.com/wp-content/plugins/super-forms/uploads/php/files/1929874c3e4cc3d7ea3d96875328fd89/pamegok.pdf
    • https://sandalyecenneti.com/wp-content/plugins/super-forms/uploads/php/files/r1h11mju8h99f1qv2tgjn6nd7e/zabibebibu.pdf
    • https://cape-electronics.com/media/file/9158711259.pdf
    • https://avigailpekelman.com/sites/default/files/file/dipesapodasaguto.pdf
    • http://studiozammuner.eu/userfiles/files/zulike.pdf
    • https://gamletaarnhuset.no/wp-content/plugins/formcraft/file-upload/server/content/files/16140ee794a160---lanubadodiket.pdf
    • https://njsolarpower.com/wp-content/plugins/super-forms/uploads/php/files/1aefae698c79d099de2be9d7eb5bb7c8/27581172934.pdf
    • http://ramenhajimetustin.com/uploads/files/34490139278.pdf
    • https://lanna-flyingclub.com/ckfinder/userfiles/files/79559782331.pdf
    • http://daedukgs.com/admin/fckeditor/data/file/20210907151716.pdf
    • https://sardavetri.it/userfiles/file/74518606127.pdf
    • https://reifenscho.de/wp-content/plugins/formcraft/file-upload/server/content/files/16131464c80968---61562747981.pdf
    • http://hoangminhphatkorea.com/webroot/img/files/27204039813.pdf
    • http://jump360.co/upload/files/20210914082844.pdf
    • https://ozmutludokum.com/userfiles/file/86133477932.pdf
    • http://omatsuri.kr/data/userfiles/files/riririfawotivixaje.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/FevRqgeaUVY/uplcv?utm_term=spotify+web+player+android
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d3f1.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xD3F1 16792 bytes
font_01_sfnt_off0000ec08.bin
17dbdd6d948cf52f5d0270c3f63be8fba19eda85c9e4f65d66534348412d9310
pdf-font-stream PDF embedded font (sfnt) at offset 0xEC08 10736 bytes
font_02_sfnt_off000104a9.bin
9714bb66d5ac9d6569f43f5c3d47e5d7ffe53c016219ebd3aadb81843dd98c86
pdf-font-stream PDF embedded font (sfnt) at offset 0x104A9 18824 bytes