Malicious PDF — malware analysis report

Static analysis result for SHA-256 7101fb7fc2375c90…

MALICIOUS

PDF

77.7 KB Created: 2021-10-09 04:23:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: a6ae0c1077b2829bcd3977670450ed6e SHA-1: 734daa62d771bffd80554c96220d4b52136616b6 SHA-256: 7101fb7fc2375c904b733e879bd2127d93b426a7d285c3c999617d6eff0ed5f2
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Numerous embedded URLs were extracted, many pointing to compromised WordPress sites or disposable hosting, indicating a link farm designed to redirect users to malicious content. The presence of PDF-specific heuristics like 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' and 'PDF_SEO_DISPOSABLE_LINK_FARM' further supports this attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9908

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://crysiq.ru/uplcv?utm_term=indigestion+pain+for+days PDF link annotation
    • http://studioaeditecne.it/userfiles/file/80968676824.pdfIn PDF document text
    • https://spbmworld.com/anaeter_capital/siteadmin/userfiles/files/dibaxaxetotuvusovowip.pdfIn PDF document text
    • https://soi.icami.mx/ckfinder/userfiles/files/famamewuguruberuxu.pdfIn PDF document text
    • https://kingyao.com/uploadfiles/files/20210922_033340_1841.pdfIn PDF document text
    • https://4wheelchile.cl/admin/uploads/file/989821846.pdfIn PDF document text
    • https://shining4u.com/wp-content/plugins/super-forms/uploads/php/files/8989ad9245e174da33a24edf19abd2cb/73579754310.pdfIn PDF document text
    • https://k85shj16h-561lt.com/contents/files/voxido.pdfIn PDF document text
    • http://aktifimmo.lu/userfiles/files/saleteduwif.pdfIn PDF document text
    • http://jeugdopdewetenschapsagenda.nl/wp-content/plugins/formcraft/file-upload/server/content/files/161450d1e6ebcf---838812795.pdfIn PDF document text
    • http://kino-cosmik.ru/sadm_files/95853807282.pdfIn PDF document text
    • http://hyunsin.net/userfiles/file/24263846023.pdfIn PDF document text
    • https://showerdrainplus.com/uploads/files/202109241006177864.pdfIn PDF document text
    • https://rsun.pro/admin/ckfinder/userfiles/files/8555096630.pdfIn PDF document text
    • http://kammerchor-lindau.com/file/pajisokalo.pdfIn PDF document text
    • https://1000families.eu/userfiles/file/65301400239.pdfIn PDF document text
    • http://residenceraffaellotorino.com/userfiles/files/rusamowuluwiriv.pdfIn PDF document text
    • http://art-ball.net/files/file/motepekeru.pdfIn PDF document text
    • https://crc.creativechange.net/ckfinder/userfiles/files/razemusogugupiturib.pdfIn PDF document text
    • http://elai.kz/upload/2021/09files/210910023711863965pgix0.pdfIn PDF document text
    • http://optikametuje.cz/userfiles/file/namutavudamukura.pdfIn PDF document text
    • http://www.studiolegalefusimorelli.com/wp-content/plugins/formcraft/file-upload/server/content/files/16137d4c66ca02---sivikibomalorujalibeja.pdfIn PDF document text
    • http://asztalosweb.hu/userfiles/file/nirunaresin.pdfIn PDF document text
    • http://linza-market.ru/upload/files/57410295262.pdfIn PDF document text
    • http://samocvet.org/foto/ck/files/pogokeditakur.pdfIn PDF document text
    • http://cupta.org/userfiles/files/20210926020723.pdfIn PDF document text
    • http://www.jindatunnel.com/up_files/file/zofepadovobozaziwunuwir.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_off0000cc76.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCC76 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e488.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE488 17096 bytes
SHA-256: e4b1aa2cb51a33078eee8e4c1a4ab811d3b8be2df7542d596b8c978ff5149913
font_02_sfnt_off00011097.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11097 10692 bytes
SHA-256: d0ec3dbe167cb3e7c05120796ed82bcbf6abc3faeef41c9fc10a441f7721769b

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