Malicious PDF — malware analysis report

Static analysis result for SHA-256 4b590e6ee527182e…

MALICIOUS

PDF

80.3 KB Created: 2020-11-23 06:10:37 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-26
MD5: 047a13401bbb9244aeaceac44b69752e SHA-1: be8ca9e3416bee669115e5cfc7ecba502868627e SHA-256: 4b590e6ee527182e5ba8d9c20ec71dc8a6d9d87e6d0f670d5581bb52aee4fda3
156 Risk Score

Malware Insights

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

The PDF file contains numerous external links, with one prominent URL leading to 'trafftec.ru'. The heuristic 'PDF_SEO_LINK_FARM' indicates a large number of external links, suggesting a link farm or redirection mechanism. ClamAV detection and ML classification strongly indicate malicious intent, specifically identified as 'Pdf.Phishing.Trojan'. The document body, though heavily obfuscated, appears to be a lure related to 'Peking university international student guide'.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • 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 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.
  • 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://trafftec.ru/aws?utm_term=peking+university+international+student+guide PDF link annotation
    • https://cdn-cms.f-static.net/uploads/4489846/normal_5fb5b2cb44c14.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4450417/normal_5fa74fa74d8a0.pdfIn PDF document text
    • https://xitukuwelup.weebly.com/uploads/1/3/4/3/134340625/7007845.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/23fd4ea5-15e1-4449-a086-45b944ad3f68/mebexifej.pdfIn PDF document text
    • https://s3.amazonaws.com/sirilagewuga/nemugukujijepubojewage.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/fef30dc9-c496-4858-9e82-f7740e9ddf93/zedigisufoxuforidozom.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/4b80287b-d8dc-4181-9e4d-e9236d05faa4/78444945044.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/6abd3b1f-f401-4520-9a11-65938eb2adc4/jijezetebiwijagusafakasol.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/9ea489bf-84c2-492d-8811-425ef7cb0936/japanese_from_zero_book_5.pdfIn PDF document text
    • https://s3.amazonaws.com/bupaxomu/leo_de_borragem.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/cd6aa175-bdd3-4ac2-bdb3-33a68e35b999/mumigovanuruvetomoba.pdfIn PDF document text
    • https://s3.amazonaws.com/busutafitufe/vofijaxokimud.pdfIn PDF document text
    • https://s3.amazonaws.com/gozifep/vuzodumaforif.pdfIn PDF document text
    • https://s3.amazonaws.com/bejokazemur/administrative_clerk_job_interview_questions_and_answers.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/0e5e807d-9b79-4772-b7fa-8dab07dda416/numerical_mathematics_and_computing_7th_edition.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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000fd52.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD52 5220 bytes
SHA-256: 00ca1ae8cb598bbe9c0c2a252fcf8a6e2d45bc52141e0b6acdded3d720dc06e4
font_01_sfnt_off00010f36.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10F36 10732 bytes
SHA-256: 75a102ea2b62d46c87bed0839c95bcca8155632f3df573870e3004a7c7bedf84

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