Malicious PDF — malware analysis report

Static analysis result for SHA-256 81e23b78e3caad4e…

MALICIOUS

PDF

84.7 KB Created: 2021-06-26 04:21:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: b4bb4b8e20abf2f0684dd428a9ec1b1b SHA-1: 6c5dae932c381b05c22f4da893753fdbd9289c8d SHA-256: 81e23b78e3caad4e01d329d2474bf3269568adb1dfbf04eeb5c06c54fe4dbe68
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous external links, many pointing to compromised WordPress sites or disposable hosting, suggesting a link farm designed to redirect users. The ClamAV detection and ML classifier strongly indicate malicious intent, likely phishing or malware delivery. No scripts were extracted, but the PDF structure itself facilitates the redirection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

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://inwebjor.ru/uplcv?utm_term=clock+calculator+and+bulb+puzzle
    • https://akdenizokullari.k12.tr/wp-content/plugins/super-forms/uploads/php/files/1gkm0m66bms4ier6h4sr0ljbv5/nivireniresibedinifagumal.pdf
    • http://abogarestudio.com/userfiles/file/59050591436.pdf
    • https://ready4use.ru/uploads/files/ritilopojufa.pdf
    • http://asesorialuishervas.com/wp-content/plugins/formcraft/file-upload/server/content/files/16078d44a47b3a---14862003453.pdf
    • https://healthcareadvisorsgroup.com/wp-content/plugins/super-forms/uploads/php/files/hqgnq5l035b5jelrmjlhhli036/45177966305.pdf
    • http://amandamaitland.com/images/file/21800616664.pdf
    • http://raduzhniy.com/wp-content/plugins/formcraft/file-upload/server/content/files/16086d71c51dca---dimisinatexafowezi.pdf
    • http://www.caslyn.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/16073a2f814519---seluxerumijilegojijemev.pdf
    • http://usateatop.com/_upload/files/21578650478.pdf
    • http://www.melloecastro.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608b373c22982---77312224481.pdf
    • https://www.ideaklinik.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/160a4859ed5fc5---bidovarelaxifugonutabojuz.pdf
    • http://pferdefreunde-brueckenhof.de/sites/default/files/userfiles/file/37201895200.pdf
    • https://www.amiunaorchestra.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160beadaeacd13---rusuwesewizutaximunopepit.pdf
    • https://deewo.de/wp-content/plugins/formcraft/file-upload/server/content/files/160bbeb8592679---samejalajowalule.pdf
    • http://autoset66.ru/admin/ckfinder/userfiles/files/bisexuveluleko.pdf
    • http://waltwhitmanclassof1965.com/clients/c/cc/ccbfa8a87e297cd67510599b8aebcb74/File/56777025175.pdf
    • https://www.audifonosdoshoydos.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bd90deb67cb---17219477799.pdf
    • https://www.18fire.com/wp-content/plugins/super-forms/uploads/php/files/d4b1565ba2a0ad213796c2a2734e8ef6/42896031927.pdf
    • https://veglifekc.org/wp-content/plugins/super-forms/uploads/php/files//niwerotabeverex.pdf
    • https://rittenhousesmiles.com/wp-content/plugins/super-forms/uploads/php/files/201e8d176970fd0a607520af231a23f2/subusovofobugu.pdf
    • https://alternativecarrepair.com/userfiles/file/54517770498.pdf
    • https://primeodontorj.com/wp-content/plugins/super-forms/uploads/php/files/e9dbeb4b35f30eb94b0078fc882b9b5e/dixafikafutuxofibugozomik.pdf
    • http://aylincinarli.com/fckfiles/file/modenuxaguba.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_off0000e72c.bin
f58e0f45a4679de2bd197f05839df3bda22ef2a8a78e4105298583bb7ec0819d
pdf-font-stream PDF embedded font (sfnt) at offset 0xE72C 10668 bytes
font_01_sfnt_off0000ff8f.bin
5c085ee70aa8598d9394564a4deee877deac5b0729a9b57c35e06f6d8328232f
pdf-font-stream PDF embedded font (sfnt) at offset 0xFF8F 17396 bytes
font_02_sfnt_off00012d72.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x12D72 16792 bytes