Malicious PDF — malware analysis report

Static analysis result for SHA-256 57a1a5665ea83734…

MALICIOUS

PDF

82.5 KB Created: 2021-03-17 06:07:47 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-06-20
MD5: ed07e4aa536128c8187e49ad1ccf3fa2 SHA-1: e7c8b0af464ed2708ec02217ec5f4227190f1b7b SHA-256: 57a1a5665ea83734f72a0c271ffaafa2112c5c23a62e1bf9b65603acd2f7399e
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains numerous external links, identified by the PDF_SEO_LINK_FARM and PDF_SEO_DISPOSABLE_LINK_FARM heuristics, suggesting it's part of a link farm designed to drive traffic to other sites. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution via these external links. The document body, though heavily obfuscated, contains text related to 'horizontal recyclerview android simplified coding', which appears to be a lure to disguise the malicious nature of the links.

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 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.
  • 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.
  • 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://resalured.ru/123?utm_term=horizontal+recyclerview+android+simplified+coding PDF link annotation
    • http://fasad-dom.site/16879683237nyf4p.pdfIn PDF document text
    • https://cdn.sqhk.co/pasepizut/jjfhhja/worlds_biggest_crossword_answers_level_2.pdfIn PDF document text
    • https://cdn.sqhk.co/jenotonolo/9hafgcv/74104589589.pdfIn PDF document text
    • https://cdn.sqhk.co/zuronenom/ahfXifV/funny_song_ringtone_download_pagalworld.pdfIn PDF document text
    • http://select-get.top/los_numeros_decimales_4_primaria_ejercicios75bpx.pdfIn PDF document text
    • https://cdn.sqhk.co/ludibipimilu/vgj6vhe/69804582254.pdfIn PDF document text
    • http://goodik.fun/8579304737405kll.pdfIn PDF document text
    • http://4bochki.ru/how_to_math_word_problemsc6n4n.pdfIn PDF document text
    • http://electriccannoz.club/mufupukukalugawadukrqjlo.pdfIn PDF document text
    • https://cdn.sqhk.co/pisapaxosabo/Sfgi3ii/wallpapers_for_laptop_hd_1080p.pdfIn PDF document text
    • http://kulinar2020.site/61730832098q1fgo.pdfIn PDF document text
    • https://cdn.sqhk.co/gejikofoxaf/xF5hch3/silosu.pdfIn PDF document text
    • http://english-10.site/expedient_homemade_firearms_vol_1v6obi.pdfIn PDF document text
    • http://cartest.pro/lipokepirovopekaluri8knqg.pdfIn PDF document text
    • https://cdn.sqhk.co/kagalitisup/cnmoNs2/strike_fighters_2_manual.pdfIn PDF document text
    • https://cdn.sqhk.co/mapetidul/hfyigif/87391310081.pdfIn PDF document text
    • https://cdn.sqhk.co/bujavenizake/RBi5tuP/bootstrap_crud_template.pdfIn PDF document text
    • http://form-copyrightservices.com/48502793579nt77u.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • https://uploads.strikinglycdn.com/files/72c69c03-b53d-4092-b243-39fdf3125e20/mivibakakerosinuxotaxani.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/d595a5ec-cf32-426d-b17c-09e6d8c93838/do_heaters_turn_off_automatically.pdfIn PDF document text
    • https://98350ace-7ac4-4f38-a9d9-579fdad8050b.filesusr.com/ugd/9b2d9b_f90d10a60ce34bd287351da76efa5fb0.pdf?index=trueIn PDF document text
    • https://48bf584d-d56c-45cf-b4f3-c1c05dce5274.filesusr.com/ugd/3f4b99_8adb8dc8c4464ce085b73856331e9c25.pdf?index=trueIn PDF document text
    • https://3c3713de-992c-4571-92b4-00afcb8cb2c1.filesusr.com/ugd/9dbdb2_9f121a8fb10649e7bf6d50c228be2c56.pdf?index=trueIn 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f507.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF507 5528 bytes
SHA-256: 2e6d89e7af8ef32a7dd8f3a8b0b75d07b216edf5a1489cf82e233f7fb6c06eb1
font_01_sfnt_off000107da.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x107DA 11112 bytes
SHA-256: 3cd6bf7ccf745c1f1e089922d21bf1977faa5c2c8ee3276eee01e3e9af8d96b1
font_02_sfnt_off00012e0b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12E0B 4324 bytes
SHA-256: 9f355172d696dda274cac500966718f112ce76951f19577ac4888987ea6471b2