Malicious PDF — malware analysis report

Static analysis result for SHA-256 4dcb8defbbc1ca65…

MALICIOUS

PDF

79.3 KB Created: 2021-09-06 14:22:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 52e977f1597f6236d695e74f61d8d774 SHA-1: 52c741c403bff52a8344d85dd71c98a7a5c1d8da SHA-256: 4dcb8defbbc1ca651ce288b2cc13ed2ed8b88a5174318ff6a4b86c270be196b3
156 Risk Score

Malware Insights

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

The PDF contains numerous links to compromised websites, identified by heuristics like 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' and 'PDF_SEO_DISPOSABLE_LINK_FARM'. The ML classifier and ClamAV detection strongly indicate malicious intent, likely to redirect users to phishing sites or download further malware. No scripts were extracted, but the link farm structure is a common tactic for initial compromise.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

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 http://www.realisthotel.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609b6b7fc4abf---kopupinaxiser.pdf In PDF document text
    • http://szpital-sulecin.pl/images/fckfiles/file/kulolovexak.pdfIn PDF document text
    • https://alutat.com/data/file/sijeguxasepe.pdfIn PDF document text
    • https://home18.ru/wp-content/plugins/super-forms/uploads/php/files/d1967c7f982cd5d647f9c74b2b498ab8/sotinadanewoxaluzenopo.pdfIn PDF document text
    • https://hotnews.md/upload/userfiles/files/vonigakevu.pdfIn PDF document text
    • http://kehlux.lu/userfiles/files/51510733216.pdfIn PDF document text
    • http://www.gradur.ba/wp-content/plugins/formcraft/file-upload/server/content/files/160a9d3355c421---sepejomejemekuxifukoju.pdfIn PDF document text
    • http://cungcapluonech.com/upload/files/29813070884.pdfIn PDF document text
    • http://svsteinfurth.de/radsportfiles/file/52772271692.pdfIn PDF document text
    • http://www.medical-psychology.gr/wp-content/plugins/formcraft/file-upload/server/content/files/1607998933a36b---nazijetemusem.pdfIn PDF document text
    • https://too.kg/wp-content/plugins/super-forms/uploads/php/files/cdc2b3f714967fb4d9e340835486d389/5192821544.pdfIn PDF document text
    • https://advicezone.org.uk/wp-content/plugins/super-forms/uploads/php/files/qcde8ql07t8lqcaufrrrpdeiui/fowuwonujuwavebiruwuxexuj.pdfIn PDF document text
    • https://securityguardsupply.com/php/uploads/file/90419171254.pdfIn PDF document text
    • http://tbff-bygg.se/img/files/64455461449.pdfIn PDF document text
    • http://themultifold.com/wp-content/plugins/super-forms/uploads/php/files/q3kn6gs2olhdq662bog4e80oh0/wixonudevujitufawibaweb.pdfIn PDF document text
    • https://www.justgym.co.za/wp-content/plugins/super-forms/uploads/php/files/0g69sca90unl4rlsa7s3ndacce/29664021230.pdfIn PDF document text
    • http://banlinhkienlaptop.com/userfiles/file/xenididak.pdfIn PDF document text
    • http://mobydick-band.de/fckdata/file/18075663783.pdfIn PDF document text
    • http://kaztelcom.kz/ckfinder/userfiles/files/39632881043.pdfIn PDF document text
    • http://c2r-auto.com/uploadfiles/file/2021070403434973499.pdfIn PDF document text
    • https://gadesign52.com/uploads/files/202108181635312428.pdfIn PDF document text
    • http://progetec.org/userfiles/files/lokaxib.pdfIn PDF document text
    • http://cyuanmei.com/userfiles/file/vabefebumidetevuz.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=transfer+file+pdf+to+docPDF link annotation
    • 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_off0000d1b0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD1B0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e9c2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE9C2 17584 bytes
SHA-256: a6099edd03a42d130f7627cedfdfbbe85d315026246b4001262f1cead976a5e3
font_02_sfnt_off00011711.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11711 10576 bytes
SHA-256: 2642e4b30f228995da34933f360ac0c1c3fa30a809c44fd992ad4606b26a5b24

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