Malicious PDF — malware analysis report

Static analysis result for SHA-256 81a7b76f931e1071…

MALICIOUS

PDF

78.6 KB Created: 2021-09-17 18:00:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: c64bb38850100df2cc5635bfe54e4939 SHA-1: d4018d5ddbe978d2599090d49fe1ed9847466d17 SHA-256: 81a7b76f931e107176468704f0b75e88547624df905e3d250575cb87df0bc047
132 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF document containing embedded JavaScript, which is often used to redirect users to malicious sites or download further payloads. The PDF also contains a link farm pointing to compromised WordPress upload storage and other disposable hosting, suggesting an attempt to obscure the true destination and evade detection. ClamAV detection as 'Pdf.Phishing.Trojan' further supports its malicious nature.

Machine Learning

  • Nyx PDF Classifier suspicious score 0.3607

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.
  • 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
  • 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://digireg.ch/upload/97178816461.pdf In PDF document text
    • https://tungafilm.com/dorceiys/ckfinder/userfiles/files/fetav.pdfIn PDF document text
    • http://eschool365.in/js/admin/uploadfiles/file/ledarifod.pdfIn PDF document text
    • https://personalloan2u.com/wp-content/plugins/super-forms/uploads/php/files/d8b29b285d491aeecb19cf0907f6c177/72304309896.pdfIn PDF document text
    • https://www.disbel.es/ckfinder/userfiles/files/goguwubazepujujowegogupef.pdfIn PDF document text
    • http://kiemdinhcan.com/Images_upload/files/83484542132.pdfIn PDF document text
    • https://tlproduct.com/userfiles/file/22362869324.pdfIn PDF document text
    • https://www.baileysmilk.com/wp-content/plugins/super-forms/uploads/php/files/8471c01957f50c841b87611e6dc3f38d/99435892919.pdfIn PDF document text
    • http://bjsixiang.com/jingkelun/userfiles/files/20210912005342.pdfIn PDF document text
    • https://f1com.ge/wp-content/plugins/super-forms/uploads/php/files/92d1ed921942cb5c4dc1882e822e6654/lajibelax.pdfIn PDF document text
    • http://spbmedax.ru/sites/default/files/uploads/waxaxevi.pdfIn PDF document text
    • http://www.191seo.com/wp-content/plugins/formcraft/file-upload/server/content/files/16143dc3baf855---worisex.pdfIn PDF document text
    • http://spreewaldpension-luebben.de/meineBilderAlbertGrundschule/file/5593801803.pdfIn PDF document text
    • http://eamenfaraz.com/cache/fck_files/file/wevajepetefemipusejixut.pdfIn PDF document text
    • https://colakcivi.com/userfiles/file/29249869554.pdfIn PDF document text
    • http://protok.pro/upload/files/fukemano.pdfIn PDF document text
    • https://maymac.info/userfiles/file/1786263655.pdfIn PDF document text
    • http://global-gypsum.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613656dfcd6ee---19859231990.pdfIn PDF document text
    • http://universalestetic.com/userfiles/file/jobitujibefisoku.pdfIn PDF document text
    • http://esenkardeslerinsaat.com/resimlerfiles/xagifa.pdfIn PDF document text
    • https://proff-doors.ru/wp-content/plugins/super-forms/uploads/php/files/31b2470c58ae2c9782ae6d5aa5a76cda/57840778805.pdfIn PDF document text
    • http://damutech.kz/upload/2021/09files/210913051738091720mle9g.pdfIn PDF document text
    • http://monthclean.com/uploads/files/202109161924128377.pdfIn PDF document text
    • https://barrier.exma.cl/ckfinder/userfiles/files/73871548311.pdfIn PDF document text
    • https://www.masismarketing.com/wp-content/plugins/super-forms/uploads/php/files/6b7910c2c0d8e392156f2b56da9eec67/wonexilikani.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/fzgW7-mxBc0/uplcv?utm_term=powerdirector+pro+versionPDF link annotation
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000dddd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDDDD 10452 bytes
SHA-256: 3d3d390a81075d8dbbbc69e286025456b70725a8bdc091591d5af6f821ab0a14
font_01_sfnt_off0000f5c4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5C4 18468 bytes
SHA-256: b02845ec586697b2156e679aa6507e258290d43a1f74b392dba6b4d8294afef6
font_02_sfnt_off00012503.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12503 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1