Malicious PDF — malware analysis report

Static analysis result for SHA-256 a3f5bf03f5b0b461…

MALICIOUS

PDF

71.5 KB Created: 2021-09-25 02:24:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: b5b58e51501ae25f6db44093fe871f0d SHA-1: fc402d8f357599d292f6197b2a5874bab9de09c6 SHA-256: a3f5bf03f5b0b461b58a8b9010ae548c7d1b7ad85054eff5be0b804aa76d5245
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file contains embedded JavaScript, which is a common technique for executing malicious code. The heuristics also indicate that the PDF acts as a link farm, pointing to multiple external URLs, some of which are hosted on compromised WordPress sites. These links likely serve as a lure or redirect to a phishing page or a second-stage malware download. The ClamAV detection and ML classifier further support its malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9840

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
  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://threadworx.com/thread/admin/uploads/file/25475274555.pdf
    • http://www.catalogodecineargentino.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614bad52c4ba0---57567511366.pdf
    • http://www.martiusstaden.org.br/js/ckfinder/userfiles/files/kabiziduzewalutugejowop.pdf
    • https://diamond-marketing.cz/soubory/xufuzuzafirikubisuna.pdf
    • http://thedewakohchang.com/image/upload/File/5447341840.pdf
    • https://drivingschoolofnorthtexas.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612fb76b9da73---xekulizowebu.pdf
    • https://hasekei.jp/userfiles/file/69127788801.pdf
    • http://whuntex.ru/userfiles/file/jevamipezugamapej.pdf
    • http://www.jindatunnel.com/up_files/file/83760423550.pdf
    • http://xn--o39a91gvwm83kbsn.net/FileData/ckfinder/files/20210919_8378E608844379DD.pdf
    • http://ghibms.com/userfiles/files/62700029689.pdf
    • http://mondoacquapiscine.com/userfiles/files/totetuzilipubifuwav.pdf
    • https://betamachinery.sa/other_files/File/jakafajafipagal.pdf
    • https://drahmetbostanci.com/wp-content/plugins/formcraft/file-upload/server/content/files/16141bcfbb77fc---vixunimugelojexifago.pdf
    • http://mobilahomedesign.com/userfiles/files/tarasudawebugajemitud.pdf
    • http://joltiy.ru/uploads/files/zowab.pdf
    • https://dacoma.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1614879f47c505---13609094479.pdf
    • http://www.globalnautique.nl/upload/files/bebakewakenowedovuxugin.pdf
    • http://nsmpublicschool.org/slbdavbatala/userfiles/file/42187454650.pdf
    • http://sensitiva.fi/UserFiles/File/48368936418.pdf
    • http://audiomaster.se/wp-content/plugins/formcraft/file-upload/server/content/files/16147f8753863d---24681307663.pdf
    • http://lynxauto.ru/userfiles/file/xamisanividijulu.pdf
    • https://szabolcsipeter.com/userfiles/file/93185568211.pdf
    • https://dolaodong.com/userfiles/file/sufesawigeninajegumej.pdf
    • http://kuryakyn.ru/userfiles/file/nekinoga.pdf
    • https://turismopontevedra.com/ckfinder/userfiles/files/96644603323.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3vuEKuznOb8/uplcv?utm_term=euro+truck+2+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_off0000b419.bin
a0163c063dc952f108775fc034271393206c46d07c1e94393e96f232245e44eb
pdf-font-stream PDF embedded font (sfnt) at offset 0xB419 17624 bytes
font_01_sfnt_off0000e114.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xE114 16792 bytes
font_02_sfnt_off0000f92b.bin
3cc75d0900b8fbb8619288ed22a208248e3afa7349c5b2ebcd8c94d5a8c2e888
pdf-font-stream PDF embedded font (sfnt) at offset 0xF92B 10312 bytes