Malicious PDF — malware analysis report

Static analysis result for SHA-256 cdb579e515aeb363…

MALICIOUS

PDF

67.3 KB Created: 2021-09-28 07:49:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: cdc31c5f8e7dc038e38f1d428a2b7d66 SHA-1: 74856a1fd9d1f319b4cd21822540f1c184a29cd6 SHA-256: cdb579e515aeb363fcd6350cffc517792187da25e5b10ded6a49f51ce70fdfdc
134 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was flagged by ClamAV as Pdf.Phishing.Trojan and an ML classifier indicated a high probability of maliciousness. The PDF contains embedded JavaScript and a large number of external URLs, many of which appear to be part of a link farm designed to obscure the final destination. This suggests the primary purpose is to redirect users to malicious sites, likely for phishing or malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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
  • 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
  • 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://cructi.ru/uplcv?utm_term=chinese+rpg+games+android PDF link annotation
    • https://sketchup360.vn/wp-content/plugins/super-forms/uploads/php/files/8c0gqmlgr2ted9hglfrimeoh31/55045548094.pdfIn PDF document text
    • http://laskod.hu/userfiles/file/nivixoziluzim.pdfIn PDF document text
    • http://huh.hu/UserFiles/File/zujolajufeleli.pdfIn PDF document text
    • https://10s317.com/uploads/files/202109231651553822.pdfIn PDF document text
    • https://bongkartuantakur.com/contents/files/91510293758.pdfIn PDF document text
    • https://minhvuongthuphap.com/upload/ck/files/nofaxu.pdfIn PDF document text
    • http://boracayg.com/FileData/ckfinder/files/20210907_864BC88C81946748.pdfIn PDF document text
    • http://due.pt/js/ckfinder/userfiles/files/sujekawatebamiruda.pdfIn PDF document text
    • https://emartdeko.pl/galeria/file/rupedugetodakagob.pdfIn PDF document text
    • http://execdentalclinic.com/uploads/ckfinder/userfiles/files/24066342107.pdfIn PDF document text
    • http://nirmalamathachurch.org/cms_uploads/image/file/boguwaxomawomam.pdfIn PDF document text
    • http://creativeindustries.ru/uploads/userfiles/file/pirixixalenenuxipen.pdfIn PDF document text
    • https://xn--lenachatka-57b.pl/uploaded/file/zuwejosupifu.pdfIn PDF document text
    • http://thestarbusan.com/FileData/ckfinder/files/20210928_39D7FBC380ADD2A8.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_off0000a4df.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xA4DF 16972 bytes
SHA-256: 841781ef78049d3e8840c9e508885d1f3cf6755c2935e417c9f7442b29049a67
font_01_sfnt_off0000d00e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD00E 10724 bytes
SHA-256: 97c86021bb414f8bf40d8ac6b2d9ece6191067bc802013b34ce1cee3062af000
font_02_sfnt_off0000e842.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE842 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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