Malicious PDF — malware analysis report

Static analysis result for SHA-256 ab51efca7310bd98…

MALICIOUS

PDF

83.5 KB Created: 2021-06-27 10:17:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 2442eb1942de5d68d1a9efbcf3b8c78c SHA-1: 5f9cc1fcf1eacd9fbab12fb380ccf37e6cda667f SHA-256: ab51efca7310bd987f2e2c0827392cfdbe7e2861df647d1b8f25a8c11ba3aed5
96 Risk Score

Malware Insights

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

The ML classifier strongly indicates maliciousness, supported by heuristics identifying the PDF as a link farm pointing to compromised CMS uploads and disposable hosting. The document body is heavily obfuscated and unreadable, suggesting it's not intended for direct user interaction but rather to facilitate navigation to external, potentially malicious, sites. The presence of numerous URLs, many hosted on compromised WordPress sites, indicates a pattern of redirecting users to further malicious content or phishing pages.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

Heuristics 5

  • 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://medvor.ru/uplcv?utm_term=types+of+general+cargo
    • http://arisutour.com/ckupload/files/32435831387.pdf
    • http://upbfassadenbau.com/upload/file/netejirulamiliraleg.pdf
    • https://amalighting.com/wp-content/plugins/super-forms/uploads/php/files/47d27981969c094adae0c024adcd081f/25420534905.pdf
    • https://canadianrelocation.net/wp-content/plugins/formcraft/file-upload/server/content/files/160892b62c5bc0---wakipep.pdf
    • http://aaaexpressheating.com/userfiles/file/25679431811.pdf
    • http://www.hptindia.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b3d4b68d2b2---lisugilubevazisod.pdf
    • https://robinio.de/wp-content/plugins/super-forms/uploads/php/files/0e87gm9nrig2orqvubkt7mn4tn/vawarakitozasefelivisusum.pdf
    • https://abeess.com/userfiles/file/rebelofonef.pdf
    • https://advicezone.org.uk/wp-content/plugins/super-forms/uploads/php/files/a3th2s11oa27bjqni7uu0ce5ne/lapososonolafumudalezej.pdf
    • http://www.norestim.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160b153dc3859b---95777184646.pdf
    • https://www.hungarianassociation.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ae9be9bde7b---mosejanedoki.pdf
    • https://klingende-zeder.de/wp-content/plugins/formcraft/file-upload/server/content/files/160b4500c204f4---pemamuvirisonojigum.pdf
    • https://snabavto.com/wp-content/plugins/formcraft/file-upload/server/content/files/160cb4796a170b---xujipenetubifinemijopag.pdf
    • https://gertiesbloomers.com/kousumi/nulook/upload/fckimages/file/peneroluvedosafilazur.pdf
    • http://kindervakantieweekdeurne.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160a07c9af2559---gibutidavizubajoninokefuv.pdf
    • http://akbmodel.com/wp-content/plugins/formcraft/file-upload/server/content/files/160cc00c53d818---xebokazaf.pdf
    • http://booklandbooks.com/userfiles/file/finumixunalebobideki.pdf
    • http://sochi-polyana.com/ckfinder/userfiles/files/15481673696.pdf
    • http://www.kmclogistics.com/wp-content/plugins/super-forms/uploads/php/files/f87728eb81b86744b08a9a95a5da8bff/52735465736.pdf
    • https://thejinglelab.com/wp-content/plugins/super-forms/uploads/php/files/ob9fdrefbmqkm358eps507j5aa/gegumomaxiwerezotimi.pdf
    • http://www.toeterloeh44.de/files/72282412034.pdf
    • https://www.cibaospalaser.com/wp-content/plugins/super-forms/uploads/php/files/bk47e0rh6fae0mact8c7chvu7l/49578176649.pdf
    • https://ocvirapuato.com.mx/wp-content/plugins/super-forms/uploads/php/files/e58ac4e1cc2718d81080f69c435597ba/voduzonivuneve.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_off0000e536.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xE536 16792 bytes
font_01_sfnt_off0000fd4d.bin
c428de2972564b2a7fa1d4e1426ab691e34914c2a179052895966d6924cdb12b
pdf-font-stream PDF embedded font (sfnt) at offset 0xFD4D 10540 bytes
font_02_sfnt_off00011586.bin
ecf4f32690032031ac72b90ac1ea88717c0cc7d91a14f61ebefd203693d13298
pdf-font-stream PDF embedded font (sfnt) at offset 0x11586 16784 bytes