Malicious PDF — malware analysis report

Static analysis result for SHA-256 4fb9389b6de1981e…

MALICIOUS

PDF

58.1 KB Created: 2021-10-07 14:04:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: bfeaf688bbe44b4502a4b84e682e0287 SHA-1: b899c6d5b72caa421557b5f70ef43ed2fa6e3c15 SHA-256: 4fb9389b6de1981efa2320c04d82f601c648d6deaee479d2b04a36d31cf928d0
154 Risk Score

Malware Insights

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

The sample is identified as malicious by ML classifiers and ClamAV, specifically as Pdf.Phishing.Trojan. It functions as a link farm, with numerous embedded URLs pointing to compromised CMS upload directories, likely intended to lure users into downloading further malicious content or phishing for credentials. The PDF structure and link farm behavior suggest a phishing or credential harvesting campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.8126

Heuristics 5

  • 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
  • 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 http://www.oknookna.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1613505afe03dd---77488631811.pdf In PDF document text
    • http://hitecds.com/userfiles/file/kebetuvakapudovixunum.pdfIn PDF document text
    • https://ntiverification.com/userfiles/file/69285919739.pdfIn PDF document text
    • http://jarosi.hu/files/file/jumonulerasage.pdfIn PDF document text
    • https://pqclass.kr/imgs/file/dedakozesovosutuzamejo.pdfIn PDF document text
    • https://seas2010.cienciaevida.pt/site/upload/file/30431653028.pdfIn PDF document text
    • https://biroestarsa.hu/uploads/file/53992845171.pdfIn PDF document text
    • https://wamsconference.com/wp-content/plugins/super-forms/uploads/php/files/d59cac83f90a874dc54f227876d2e293/71090729811.pdfIn PDF document text
    • https://wurstfargo.com/wp-content/plugins/super-forms/uploads/php/files/ecaf8b0e224f2b66afa37c96ee6ee70d/romonujajiruzor.pdfIn PDF document text
    • https://sketchup360.vn/wp-content/plugins/super-forms/uploads/php/files/7vv1r5sm28e8d0s12j1na3u230/lanavuvogota.pdfIn PDF document text
    • http://k3projekt.pl/uploads/userfiles/files/xetanipadanozimenalasem.pdfIn PDF document text
    • https://isosklo.cz/uploads/silodev.pdfIn PDF document text
    • http://melvin.cz/data/xabanupeduneg.pdfIn PDF document text
    • http://full814.com/upload/files/nawivesafazopesekolavaf.pdfIn PDF document text
    • http://www.bridalchapel.com/wp-content/plugins/formcraft/file-upload/server/content/files/16156da3cb9a8b---kusoxebowutexavi.pdfIn PDF document text
    • http://astorandblack.net/emailer/userfiles/file/75520354257.pdfIn PDF document text
    • http://bangladeshceramicsociety.com/uploads/editor/files/jixorazimev.pdfIn PDF document text
    • http://trunglamdecor.com/uploads/userfiles/file/mukinowuzeranitozelegur.pdfIn PDF document text
    • http://www.stockholmswingallstars.com/wp-content/plugins/formcraft/file-upload/server/content/files/16148fda593946---zimekeje.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/fzgW7-mxBc0/uplcv?utm_term=integrated+algebra+june+2011+answersPDF link annotation
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b40b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB40B 10912 bytes
SHA-256: 33469eafc1a2d59b83a327592117140b833717f7f1f580a8bea1db9cdf37055d

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