Malicious PDF — malware analysis report

Static analysis result for SHA-256 c761f8a8a50ba237…

MALICIOUS

PDF

71.5 KB Created: 2021-03-14 19:27:02 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: a5760809ea4f04c11491cc54cddee23f SHA-1: 127857d387a22875863ff52625a02fdd06fe1da7 SHA-256: c761f8a8a50ba2378f1b08ede0269cc3ad93c43c7a41861d03c5162e40800431
126 Risk Score

Malware Insights

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

The sample is a PDF file flagged by ClamAV as Pdf.Phishing.Trojan and by an ML classifier as malicious. It contains numerous external URIs, with a prominent one being https://jacksth.ru/strik. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates the document is a link farm on disposable hosting, suggesting a phishing or malware distribution attempt. While no scripts were explicitly extracted, the nature of the heuristics and the embedded URLs point towards a malicious intent to redirect users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

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 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://jacksth.ru/strik?utm_term=dirt+devil+featherlite+filter
    • https://cdn-cms.f-static.net/uploads/4501998/normal_5fdb853648308.pdf
    • https://tagakokiginozol.weebly.com/uploads/1/3/0/7/130775172/39322219c.pdf
    • https://cdn.sqhk.co/befozaxulot/eiNgcid/do_hashtags_work_on_instagram_reels.pdf
    • https://rigivopamakor.weebly.com/uploads/1/3/4/8/134869382/9c363156bf6.pdf
    • https://static.s123-cdn-static.com/uploads/4471249/normal_5ff61299c6687.pdf
    • https://cdn.sqhk.co/bogabixexuja/Jhcgf5r/red_fireman_hat_toddler.pdf
    • https://static.s123-cdn-static.com/uploads/4490516/normal_6009235284f58.pdf
    • https://cdn.sqhk.co/wolanojijen/lTxhFif/big_wings_for_sale.pdf
    • https://static.s123-cdn-static.com/uploads/4387060/normal_5fee91d3b006b.pdf
    • https://baboxubawuxi.weebly.com/uploads/1/3/4/6/134666135/jiwivo_ridega.pdf
    • https://welavomuwaj.weebly.com/uploads/1/3/4/6/134633166/supamedimewigebuga.pdf
    • https://cdn.sqhk.co/nuzifixe/BjbLoji/3776651728.pdf
    • https://cdn.sqhk.co/jutigurotow/hdKibwH/elife_username_and_password_reset.pdf
    • https://teduzagegoxow.weebly.com/uploads/1/3/4/4/134400331/1717193.pdf
    • https://cdn-cms.f-static.net/uploads/4389353/normal_601d3849f3966.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://s3.amazonaws.com/posaxugidut/pupedowizikurus.pdf
    • http://mopezit.epizy.com/cookery_classes_listening_answer.pdf
    • https://s3.amazonaws.com/teximikamukubo/best_text_editor_for_android_phone.pdf
    • http://wobemiko.epizy.com/acc_ltd_annual_report_2018.pdf
    • https://1dfef493-bba3-4db0-89f7-7cef958ceea2.filesusr.com/ugd/3dbeb3_ee57ac5352ed4deab8372b470437026c.pdf?index=true
    • https://s3.amazonaws.com/jebokizez/how_to_find_the_tone_of_a_poem.pdf
    • http://retesatitogeli.epizy.com/zuvelabomegemilopis.pdf
    • https://0926596c-b1e6-4473-87d6-fed2e709bfeb.filesusr.com/ugd/e2a635_1d06ac00cd9b4b1eaf0a765bc517ab33.pdf?index=true
    • 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_off0000d8f1.bin
9ce98b6d3c2947db94343621220bfa38f77140d9e48b7d96198aa8bc839f63ab		 pdf-font-stream PDF embedded font (sfnt) at offset 0xD8F1 4876 bytes
font_01_sfnt_off0000e98b.bin
216d51fa6f1513771bf7995cec28a4799539c847887de644c50fa102904f7160		 pdf-font-stream PDF embedded font (sfnt) at offset 0xE98B 11112 bytes

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