Malicious PDF — malware analysis report

Static analysis result for SHA-256 58863130f9b01891…

MALICIOUS

PDF

72.2 KB Created: 2021-05-27 11:54:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 0075fd74bcd7faf5f2076eeb07685ce3 SHA-1: 312c172a315a5b1a3ee8d362988da5216b2016ad SHA-256: 58863130f9b01891e8d17cf27e52894fb818d43140591922e77d1e29b668d87f
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous links to external websites, many hosted on compromised CMS platforms, suggesting a link farm or phishing lure. The document body, though heavily obfuscated, contains references to 'wkhtmltopdf' and 'how to write anything pdf free online', reinforcing the lure of a free PDF download to redirect users to potentially malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 6

  • 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.
  • 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://krisoc.ru/uplcv?utm_term=how+to+write+anything+pdf+free+online
    • http://www.sunaryem.com.tr/wp-content/plugins/super-forms/uploads/php/files/6s171aaflet7b55u21p9j29n72/81814012163.pdf
    • https://alsterparkett.de/wp-content/plugins/super-forms/uploads/php/files/mhtigm90g4uq3tmtmbljnlt1dv/14263905401.pdf
    • https://isosklo.cz./uploads/datisu.pdf
    • https://deewo.de/wp-content/plugins/formcraft/file-upload/server/content/files/16085cc1bc446f---41293328839.pdf
    • http://www.kocay.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/160883fa17af76---47525974006.pdf
    • https://vuaship.com/wp-content/plugins/super-forms/uploads/php/files/mm56b5tmg3imi24gpvtfls8cp7/41859725129.pdf
    • https://www.beachesbrewing.com/wp-content/plugins/super-forms/uploads/php/files/e578fee0b7df8b7a52dc077f647b0883/tumekakaxu.pdf
    • http://mirandatutoringcentre.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1607cb82ebcc83---botowujolegafovubeti.pdf
    • https://www.landalastadservice.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609c14100dddb---voratabigitilusoz.pdf
    • https://tkpmission.org/wp-content/plugins/formcraft/file-upload/server/content/files/160a47717245db---13464290099.pdf
    • http://limpiasol.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606c83517726e---96014663766.pdf
    • https://siphouse96.com/wp-content/plugins/super-forms/uploads/php/files/1c755006afb01015ba6885611e0ac1e5/45104971857.pdf
    • https://auf.vn/wp-content/plugins/super-forms/uploads/php/files/d8ts9aft1201o72fcv3ijajtd7/vizopafawesek.pdf
    • http://jrpst.pl/userfiles/file/81019000534.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • 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://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ddf6.bin
7019b0c1618c7010227ff9280c567e2fa56255bd973df3a6bd7ad23160be5b8c		 pdf-font-stream PDF embedded font (sfnt) at offset 0xDDF6 5280 bytes
font_01_sfnt_off0000f003.bin
e0d9bd7924020fc14084099fd749d552537b3c088668370825fac877b6262ae9		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF003 10560 bytes

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