Malicious PDF — malware analysis report

Static analysis result for SHA-256 27ad59ae16b88842…

MALICIOUS

PDF

88.4 KB Created: 2021-04-07 06:27:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: f2b1542c19d538eb5dd9ff1743990a8f SHA-1: 30efcddb0bfbc00c26f4886c063ae33422093b83 SHA-256: 27ad59ae16b88842ff5a6327d5e0a9bd1c8a5dd3ceca204c40d86a8d0a2894a8
156 Risk Score

Malware Insights

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

The file is identified as malicious by ClamAV and an ML classifier, with critical heuristics indicating it functions as a PDF link farm. It contains numerous external URLs, with zajinet.ru being a primary example. The document body is heavily obfuscated, but the presence of PDF_SEO_LINK_FARM and PDF_URI heuristics strongly suggests a malicious intent to redirect users to other sites, potentially for 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://zajinet.ru/award?keyword=born+haber+cycle+problems+pdf
    • https://static.s123-cdn-static.com/uploads/4497344/normal_5fdcfa828a821.pdf
    • https://cdn.sqhk.co/mosepoxik/ahajgOG/79315927267.pdf
    • https://cdn.sqhk.co/sadirorig/zZjeijI/29823993672.pdf
    • http://lasabobobatir.22web.org/97157262821.pdf
    • https://cdn.sqhk.co/loganidob/jhDfhcX/green_bay_schedule_2020-_21.pdf
    • https://cdn-cms.f-static.net/uploads/4417216/normal_600f10a883d17.pdf
    • https://cdn.sqhk.co/libuzewis/riangic/got_milk_bubble_tea_house.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://uploads.strikinglycdn.com/files/921f106e-567e-4c6d-b53b-6a53f3cd085c/suzuza.pdf
    • https://uploads.strikinglycdn.com/files/c1ec28d8-0c51-47ef-8c51-910122d0f09e/wukenotefezar.pdf
    • https://uploads.strikinglycdn.com/files/56731489-a5ab-4ada-9e6a-4e44f8b7acc5/what_brand_router_does_centurylink_use.pdf
    • https://uploads.strikinglycdn.com/files/3e54946d-6f01-4a77-9751-8b0e413ec22c/zozaruwo.pdf
    • https://uploads.strikinglycdn.com/files/1fdd2168-ea9c-446a-9274-15a777a4a052/is_the_dmv_open_today_in_south_carolina.pdf
    • https://e714dd98-3e42-4604-aba1-6d4b2506b1a8.filesusr.com/ugd/742965_8470b017f6af44ef9749c33cf7f1ebfb.pdf?index=true
    • https://uploads.strikinglycdn.com/files/4f7f6143-1500-4ae1-805e-fcb45cbe87e9/24_hours_quote.pdf
    • http://pefoxaxogux.epizy.com/advanced_automobile_technology.pdf
    • https://2f2ab42d-e0b4-4bd3-aa50-2430da1ff5fc.filesusr.com/ugd/eaf48f_304c72d8eb304a0fab1c296c951135fd.pdf?index=true
    • https://uploads.strikinglycdn.com/files/bd6d28fa-9226-4904-8c51-970de94da010/anatomy_and_physiology_book_for_dummies.pdf
    • http://taperimogitunal.epizy.com/40560538744.pdf
    • https://uploads.strikinglycdn.com/files/6193ddec-fe6e-4194-a566-14197200f107/mozafanorofubagit.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_off0001178b.bin
4bde5f6be3cff52df74c812d1dfe07549b4b583243eb1daf12cf26709be97fa7		 pdf-font-stream PDF embedded font (sfnt) at offset 0x1178B 5688 bytes
font_01_sfnt_off00012abd.bin
e7f47216b12784ce2a3515926ab0cee35cd7954db9c241984d7feedc21a9155d		 pdf-font-stream PDF embedded font (sfnt) at offset 0x12ABD 11876 bytes

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