Malicious PDF — malware analysis report

Static analysis result for SHA-256 f6638aa6823ec5c5…

MALICIOUS

PDF

85.0 KB Created: 2021-09-12 19:28:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 3a6b80679bd0b8c2d4df8d3ec9bd10bd SHA-1: 9236597e475e5877cd80149bb8b22e1d49c70025 SHA-256: f6638aa6823ec5c57ca0f4c0c8696662df794e6cc266e8936ad2af1a644f3edb
156 Risk Score

Malware Insights

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

The PDF contains numerous links, many pointing to compromised CMS upload directories and disposable hosting, indicative of a link farm or phishing lure. ClamAV detected this file as 'Pdf.Phishing.Trojan', and the ML classifier also flagged it as malicious. The primary attack pattern involves redirecting users through these links, likely to a malicious site or for SEO poisoning.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://www.reliancecareuk.com/wp-content/plugins/super-forms/uploads/php/files/5863f8d375b2dde99de7d1067eb3b1e9/29426999526.pdf
    • https://www.autopsrus.com/ckfinder/userfiles/files/zovas.pdf
    • http://vakaruinzinerija.lt/userfiles/file/53522878454.pdf
    • https://makojudo.pl/zdjecia/fck/file/famabazanivekizunubodofox.pdf
    • https://humanistbeauty.com/wp-content/plugins/super-forms/uploads/php/files/ortlb3692djq5aq0al96lnaqdv/demifedonobunulopavo.pdf
    • https://www.jemelectric.com/wp-content/plugins/formcraft/file-upload/server/content/files/161327c4ad8aed---37468717293.pdf
    • http://cn-biyoute.com/d/files/sapuvibudixunid.pdf
    • http://mirai-kankyo.com/userfiles/files/resenuvasegobep.pdf
    • http://english-island.pl/wp-content/plugins/super-forms/uploads/php/files/ji1tbdaq457pq33csldk1j9gv7/zebuja.pdf
    • https://copacndg.com/images/uploads/files/jilofufunipawakokonal.pdf
    • http://uitetenindex.nl/images/uploads/85823692537.pdf
    • http://tao-oita.com/admin/upload_filesfile/fevawajixumuref.pdf
    • http://stickers-moins-cher.com/userfiles/stickers-moins-cher.com/file/21569037167.pdf
    • http://jagatjyotischool.org/jagatjyotischool/userfiles/file/togeterodijiguvutefadag.pdf
    • https://glbtrader.com/userfiles/file/xigakozuvolujeg.pdf
    • http://eshop-kocicinadeje.cz/files/file/fezirusiteretibidugulebom.pdf
    • https://mavismanagement.com/wp-content/plugins/formcraft/file-upload/server/content/files/16135316222763---36862808899.pdf
    • https://htapigroup3.com/contents/files/84198401080.pdf
    • http://allier.proximeo.com/ckfinder/userfiles/files/169666662.pdf
    • http://studiotecnicofrisoli.com/userfiles/files/zisoxijiranuxane.pdf
    • http://syarmarka.ru/userfiles/files/banedudozan.pdf
    • http://www.vljainandco.com/userfiles/files/20108562422.pdf
    • https://thaibamboorestaurant.ca/phpsites/bard_ford/uploads/file/94939911232.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/GLLx1DTH0VQ/uplcv?utm_term=family+island+unlimited+mod
    • http://crossfit28.com.s125853.gridserver.com/siteuploads/editorimg/file/95880249553.pdf
    • 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_off0000e93d.bin
1a34d064156ac8f7a6bf2a62b332982dd58a65937d1abfd3204e38773002a920
pdf-font-stream PDF embedded font (sfnt) at offset 0xE93D 17352 bytes
font_01_sfnt_off00011660.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x11660 16792 bytes
font_02_sfnt_off00012e77.bin
6d68c57421f584aaeb02e567bbc5b9f88e0c470b157937027a47eda6e6c0d41d
pdf-font-stream PDF embedded font (sfnt) at offset 0x12E77 10500 bytes