Malicious PDF — malware analysis report

Static analysis result for SHA-256 3f6861927ff3bc6e…

MALICIOUS

PDF

75.3 KB Created: 2021-06-13 17:41:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: efe1173ca961591e1b22357a18ad88fe SHA-1: e622fb8f34ff9030fe002d40eb36bf3db396fad5 SHA-256: 3f6861927ff3bc6e914e01b39f1a3e68d420f75655a2fe9890834e02565ddac7
156 Risk Score

Malware Insights

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

This PDF file contains a large number of external links, many pointing to other PDF documents hosted on various platforms. The heuristic 'PDF_SEO_LINK_FARM' indicates a mass of external PDF links, suggesting a tactic to manipulate search engine results or distribute further malicious content. The presence of a ClamAV detection for 'Pdf.Phishing.Trojan' and a high ML score further support its malicious nature. The primary IOC is the initial URL which likely serves as an entry point to this link farm.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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://laborke.ru/pbw?utm_term=chemical+elements+names+and+symbols
    • https://cdn-cms.f-static.net/uploads/4497093/normal_6064b4b592193.pdf
    • https://cdn-cms.f-static.net/uploads/4468294/normal_605717d4cc6fe.pdf
    • https://xumijarivibamow.weebly.com/uploads/1/3/5/3/135339210/sivuruferarurukel.pdf
    • https://cdn-cms.f-static.net/uploads/4459464/normal_60bed3fbbad77.pdf
    • https://zitipijasidigor.weebly.com/uploads/1/3/0/8/130874434/juliminikitabo_vakesogalomi.pdf
    • https://cdn-cms.f-static.net/uploads/4466366/normal_603f966c23613.pdf
    • https://sajefabavasa.weebly.com/uploads/1/3/2/7/132710755/0ed2a17e201b0.pdf
    • https://cdn-cms.f-static.net/uploads/4372087/normal_60b7ce1c77ec5.pdf
    • https://zofiludel.weebly.com/uploads/1/3/5/3/135347527/b9981c903.pdf
    • https://static.s123-cdn-static.com/uploads/4473971/normal_5fce50aadc6bb.pdf
    • https://vakurizilobiwil.weebly.com/uploads/1/3/0/9/130969742/vejutigafatu.pdf
    • https://static.s123-cdn-static.com/uploads/4484376/normal_5fcde3a21c142.pdf
    • https://cdn-cms.f-static.net/uploads/4384050/normal_602fda468298b.pdf
    • https://lojapajarete.weebly.com/uploads/1/3/4/5/134521209/269442.pdf
    • https://cdn-cms.f-static.net/uploads/4473637/normal_5fe958f0c7a05.pdf
    • https://cdn-cms.f-static.net/uploads/4424349/normal_60c38a94b21c7.pdf
    • https://static.s123-cdn-static.com/uploads/4385235/normal_6002a04bd4b19.pdf
    • https://static.s123-cdn-static.com/uploads/4464052/normal_60081ee7e4931.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://uploads.strikinglycdn.com/files/31625a2c-1055-4c24-a293-3caa0b86b89a/jiloruginotuxumava.pdf
    • https://uploads.strikinglycdn.com/files/8648ce0a-8c98-44a1-a60a-9b6b093456a3/sakikamam.pdf
    • https://uploads.strikinglycdn.com/files/7895a6cf-c481-489f-9d52-ca59db72c3eb/lista_de_verbos_en_ingles_en_pasado_y_presente_simple.pdf
    • 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_off0000e895.bin
1250205a6d5e7127ecc1e40432809d99acc35f4d2d2cff17c516a1043b534800
pdf-font-stream PDF embedded font (sfnt) at offset 0xE895 5232 bytes
font_01_sfnt_off0000fa35.bin
97f79c4079087158e153eb40e991bb08646ede2cc7983566f1adefc0341e7e66
pdf-font-stream PDF embedded font (sfnt) at offset 0xFA35 11240 bytes