Malicious PDF — malware analysis report

Static analysis result for SHA-256 3cf9275a16dcdb56…

MALICIOUS

PDF

77.6 KB Created: 2021-03-29 03:14:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 7909d1880704ac4c2e05081df5d448fc SHA-1: 3438b3e4197d324e28c6bef898841740271c7ac5 SHA-256: 3cf9275a16dcdb563e59b04b039edfe005e9cf0c2513ffaa85051ba4ce696644
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF file contains a large number of external links, many of which point to PDF files hosted on cloud storage services, suggesting a link farm for SEO manipulation. One of the external URIs, 'https://vilenefex.ru/strik?utm_term=dell+precision+390+motherboard+drivers', is hosted on a domain with a suspicious reputation and is likely the primary malicious payload delivery mechanism. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://vilenefex.ru/strik?utm_term=dell+precision+390+motherboard+drivers
    • https://cdn.sqhk.co/nunemiziku/SBtiaJu/bigusodaxodexifurof.pdf
    • https://cdn.sqhk.co/firijanab/gjmPAdE/zowebimarav.pdf
    • http://tegubija.mypressonline.com/centropomus_undecimalis.pdf
    • http://lisuzigerob.mygamesonline.org/grade_9_spelling_words.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://s3.amazonaws.com/fogibi/iobit_driver_booster_pro_full_crack.pdf
    • https://s3.amazonaws.com/zozofufulolig/federal_reserve_balance_sheet.pdf
    • https://167c8e7b-8160-49a2-a88e-f26749d647c8.filesusr.com/ugd/1ad47d_150f1a01404c4316943f4759d627bde4.pdf?index=true
    • https://s3.amazonaws.com/viboxikuz/epson_1430_print_head_cleaning.pdf
    • https://60b161a2-b511-46bc-b48c-7ca4331f2db3.filesusr.com/ugd/34b71b_22bcb7f6c13d4b2da89a4c6f94189c51.pdf?index=true
    • https://uploads.strikinglycdn.com/files/2ec2ec89-280d-4ed2-b72d-63ea1d3a5478/que_es_una_linea_del_tiempo_ejemplos.pdf
    • https://a1f0096d-76f5-425c-b826-5ccbd312c1bc.filesusr.com/ugd/8f8c07_22887c1aef1a47f5b0050336f813954c.pdf?index=true
    • https://5e3b32e6-a537-4a58-a531-ef303a468713.filesusr.com/ugd/120874_e89d8814ccd7470aa6c5d23130e56b49.pdf?index=true
    • https://54fa3baf-6954-44a2-98df-2137f0cc340f.filesusr.com/ugd/14b79e_9446179690e64c97904eb309df76ad90.pdf?index=true
    • https://s3.amazonaws.com/roxawo/69561389257.pdf
    • https://s3.amazonaws.com/gixawetopoli/vemusupi.pdf
    • https://uploads.strikinglycdn.com/files/f8cd6ef1-74b6-440e-8451-7231cbb6342d/academic_writing_skills_definition.pdf
    • https://uploads.strikinglycdn.com/files/c6544f3b-83c5-48b4-8e29-28222982fc23/shark_navigator_vacuum_maintenance.pdf
    • https://97a45c9e-1ab5-462a-bfe2-fded34b9a8b9.filesusr.com/ugd/b50c55_ab23dfe8e3de48b6bab9eb274b2bb26c.pdf?index=true
    • 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://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f044.bin
fe5f7c79ea625651023f847a430feb9eef73cdc4598693f444a69c7d419bc54f		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF044 5976 bytes
font_01_sfnt_off00010465.bin
b93a13e46138d6768446be2731d12f483049be8fdacde8cf0ebe3f58ec7ad826		 pdf-font-stream PDF embedded font (sfnt) at offset 0x10465 10752 bytes

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