Malicious PDF — malware analysis report

Static analysis result for SHA-256 11bac28bae755479…

MALICIOUS

PDF

72.2 KB Created: 2021-09-01 04:17:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 71522478e0e1751b663e60611a0c2090 SHA-1: 5a53b3c086ec95f14f11db14cd4561fec9de91dd SHA-256: 11bac28bae75547938f220cc701155e34c76fbeb8d294585c7093d68feb12f72
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It functions as a link farm, directing users to numerous external websites, many of which are hosted on compromised CMS platforms or disposable domains. The presence of PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics strongly suggests a phishing or malware distribution campaign. No scripts were extracted, but the PDF structure itself facilitates the redirection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://medvor.ru/uplcv?utm_term=why+do+bacteria+have+restriction+enzymes PDF link annotation
    • http://sabaispa.net/userfiles/file/38706308347.pdfIn PDF document text
    • http://portaldeaquidauana.com.br/ckfinder/userfiles/files/zenedowuj.pdfIn PDF document text
    • http://frigotechreina.com/userfiles/files/93598237952.pdfIn PDF document text
    • https://ailani.org/wp-content/plugins/super-forms/uploads/php/files/1b87739f8551bb93384d8dd212a7d842/leloromoj.pdfIn PDF document text
    • http://smartmedicaleg.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b4dcdfa5694---57932754880.pdfIn PDF document text
    • http://unseretochter.ch/images/file/40783137752.pdfIn PDF document text
    • http://cpils.com/userfiles/file/90480787444.pdfIn PDF document text
    • http://www.franklinwebdesign.com/wp-content/plugins/formcraft/file-upload/server/content/files/16073c069434cf---52972017953.pdfIn PDF document text
    • http://reliancefla.com/admin/images/file/68775355266.pdfIn PDF document text
    • https://flycam.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/160779d9f21e29---80923229030.pdfIn PDF document text
    • https://cailux.lu/userfiles/files/wejubopotidogedale.pdfIn PDF document text
    • https://merydian.pl/nowymerydian/userfiles/file/67090865061.pdfIn PDF document text
    • http://www.patricktennis.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1606ec02a34341---kuvotezinakazixezuxuwame.pdfIn PDF document text
    • http://hellnocancershow.com/wp-content/plugins/formcraft/file-upload/server/content/files/16094102e5efa0---romarakilibemiw.pdfIn PDF document text
    • http://steclotildehorton.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160b383dad51eb---95518875189.pdfIn PDF document text
    • http://jiin-torng.com/uploadfiles/20210811100627.pdfIn PDF document text
    • https://mm-podium.ro/userfiles/file/nekogovez.pdfIn PDF document text
    • https://www.ikedatosou.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b7e9a29cefd---99643208551.pdfIn PDF document text
    • http://veitali.com/upload/files/bapegebonegusetaxeg.pdfIn PDF document text
    • http://www.logomarcanet.com/userfiles/file/82709233267.pdfIn PDF document text
    • https://hps-gruppe.com/wp-content/plugins/super-forms/uploads/php/files/gq8aoshap7uuujt2ukt8sg975i/6024700494.pdfIn PDF document text
    • https://zegabilisim.com/calisma2/files/uploads/7226214165.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • 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_off0000b7a1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB7A1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000cfb8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCFB8 10960 bytes
SHA-256: 2a90d525baa7415c6144e20dc2e41df18301761ffca57f46e2e30c3bb2280acc
font_02_sfnt_off0000e90a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE90A 17100 bytes
SHA-256: d419e62ff63ac9e26fa748f5ff9e11d948f2a31ac11375708c5500cb5ec7589a

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