Malicious PDF — malware analysis report

Static analysis result for SHA-256 4c3d1bd5f2296f9e…

MALICIOUS

PDF

71.9 KB Created: 2021-06-04 16:30:00 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: ef5cd7083ee19516c7a830be541d7be6 SHA-1: ad377cc14841ad6fa7c7162185a8415ff573842a SHA-256: 4c3d1bd5f2296f9e336fc692fa79d24463494a6eae6617a0e414d806547249e5
156 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The heuristic firings suggest it contains a link farm with numerous external PDF links, including a suspicious URL pointing to dugedepap.ru. The document body, though heavily obfuscated, contains metadata related to PDF creation and a search term, reinforcing the lure aspect.

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://dugedepap.ru/123?utm_term=cambridge+english+empower+c1+pdf+descargar
    • https://cdn-cms.f-static.net/uploads/4409806/normal_606258158c84e.pdf
    • https://rafafokisot.weebly.com/uploads/1/3/4/7/134738004/54a1d5.pdf
    • https://kawuwulaf.weebly.com/uploads/1/3/3/9/133987507/6d996ff.pdf
    • https://mizemajawoxulu.weebly.com/uploads/1/3/1/4/131437858/e7a01fbe5.pdf
    • https://cdn-cms.f-static.net/uploads/4410004/normal_6043fae78a551.pdf
    • https://static.s123-cdn-static.com/uploads/4369524/normal_5feeac00a740d.pdf
    • https://cdn-cms.f-static.net/uploads/4470687/normal_606e89ea0974c.pdf
    • https://koximewi.weebly.com/uploads/1/3/0/7/130775363/257319.pdf
    • https://cdn-cms.f-static.net/uploads/4419204/normal_603d3b184ce1b.pdf
    • https://lobavasato.weebly.com/uploads/1/3/1/4/131483685/kigapoguv-wifevi.pdf
    • https://static.s123-cdn-static.com/uploads/4487618/normal_5fdcbc5e5f791.pdf
    • https://namovanuzo.weebly.com/uploads/1/3/1/6/131606642/vanilozix_dafalu_teriniwali_sotir.pdf
    • https://cdn-cms.f-static.net/uploads/4391305/normal_604cbbc1bfd70.pdf
    • https://cdn-cms.f-static.net/uploads/4527747/normal_605a0281d8c74.pdf
    • https://guxovegetixewaz.weebly.com/uploads/1/3/2/3/132302910/f69045abc320.pdf
    • https://static.s123-cdn-static.com/uploads/4490371/normal_5ffdc7bf13f69.pdf
    • https://static.s123-cdn-static.com/uploads/4483361/normal_5ffcfb478c5b4.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://uploads.strikinglycdn.com/files/ddf59c58-4212-46b6-bbbe-63fbbb07016c/jorge_bucay_cuentos_cortos_de_amor.pdf
    • https://uploads.strikinglycdn.com/files/43cdd729-70f2-473a-b287-c724a3d2d3e2/python_list_comprehension_multiple_variables.pdf
    • https://uploads.strikinglycdn.com/files/8d9441c2-0f1e-4dc9-a7c5-ce33ded46f30/91662999130.pdf
    • https://uploads.strikinglycdn.com/files/e072ed09-5dd9-4616-b552-cf643a0d1b11/nilubuti.pdf
    • https://uploads.strikinglycdn.com/files/291dea87-ad84-4e31-a4c0-9b46be1c6a3f/voforijosenagixumi.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_off0000d7c8.bin
e904e58e75804868b6f725a34156833e7493bc8f9ea3980e5c4e924fe7ae27ed
pdf-font-stream PDF embedded font (sfnt) at offset 0xD7C8 5756 bytes
font_01_sfnt_off0000eb3b.bin
9d8f083c51f192fe985ce0b708618ac2bb48c8f05daa6f2db28f498bb66f5b62
pdf-font-stream PDF embedded font (sfnt) at offset 0xEB3B 11444 bytes