Malicious PDF — malware analysis report

Static analysis result for SHA-256 287ef1b55e908cd2…

MALICIOUS

PDF

75.7 KB Created: 2021-03-11 05:25:59 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 5c60e261143dc775a877eb06d0e6b3e6 SHA-1: 4142955d8919ecfbf0aa46e21e4426e040fe727b SHA-256: 287ef1b55e908cd2f8e127ca88d045f8a450b15050cad1620e05d391b468d053
136 Risk Score

Malware Insights

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

The PDF contains invisible links that lead to a CAPTCHA-themed lure, specifically pointing to 'https://s3.amazonaws.com/tumasun/captcha_background_images.pdf'. One of the embedded URIs, 'https://nipisod.ru/award?keyword=conjunction+exercise+for+class+4+pdf', is also suspicious. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • Invisible PDF links to CAPTCHA-themed web lure high PDF_CAPTCHA_LINK_LURE
    PDF contains invisible clickable link annotations that point to a CAPTCHA/capcha-themed web path. This is a common phishing and ClickFix-style routing pattern: the PDF itself is inert, while the linked page performs the credential prompt or fake verification.
  • 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://nipisod.ru/award?keyword=conjunction+exercise+for+class+4+pdf
    • https://cdn-cms.f-static.net/uploads/4389570/normal_5fd27dae58265.pdf
    • https://cdn.sqhk.co/sujubowip/hhgX7Fs/yamaha_aerox_2020_colors.pdf
    • https://cdn.sqhk.co/jixuvepabu/ixdtI7U/57970785464.pdf
    • https://cdn.sqhk.co/kakovavop/ijihbhh/54447003153.pdf
    • https://cdn.sqhk.co/banamasuvaj/gjrijji/woforuwokora.pdf
    • https://cdn-cms.f-static.net/uploads/4368493/normal_5fea11b50a549.pdf
    • https://cdn-cms.f-static.net/uploads/4379855/normal_6027b15a6a9ea.pdf
    • https://cdn-cms.f-static.net/uploads/4451955/normal_5fd64f80ddf10.pdf
    • https://cdn-cms.f-static.net/uploads/4413865/normal_6032fb5472b74.pdf
    • https://cdn-cms.f-static.net/uploads/4366628/normal_60252ab82938d.pdf
    • https://cdn.sqhk.co/rerunaropiz/iedOhjb/2xl_mx_offroad_apk_mod.pdf
    • https://cdn-cms.f-static.net/uploads/4450336/normal_60360e1e06623.pdf
    • https://static.s123-cdn-static.com/uploads/4413120/normal_5ffcd70bc107e.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://s3.amazonaws.com/pilazi/exploring_science_year_7_worksheets.pdf
    • https://s3.amazonaws.com/pubopelej/82625017745.pdf
    • http://kirogebi.epizy.com/1809781474.pdf
    • https://s3.amazonaws.com/tumasun/captcha_background_images.pdf
    • https://s3.amazonaws.com/lemefofutomapox/anjali_raghav_all_image.pdf
    • https://s3.amazonaws.com/nagev/17602871029.pdf
    • http://tujatubaniza.epizy.com/battery_percentage_android_10.pdf
    • https://s3.amazonaws.com/geradi/thai_basic_phrases.pdf
    • https://s3.amazonaws.com/wozowuledij/clockwise_and_anticlockwise_turns_worksheet.pdf
    • http://rowavironipomiz.epizy.com/16988626089.pdf
    • https://s3.amazonaws.com/bejikefowu/ashab_e_kahf_story_in_urdu.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_off0000ebce.bin
b25d4a25f1d518eb452ede9428c62d931c9ac34d62ee859b271b8b2d4b44bccf		 pdf-font-stream PDF embedded font (sfnt) at offset 0xEBCE 5288 bytes
font_01_sfnt_off0000fde4.bin
548a79c3f8fde21e3dddd8c205cc9e9f9a382f47ac43c2c51383640b15909d9e		 pdf-font-stream PDF embedded font (sfnt) at offset 0xFDE4 10228 bytes

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