Malicious PDF — malware analysis report

Static analysis result for SHA-256 c31f275047af2de9…

MALICIOUS

PDF

68.9 KB Created: 2021-02-15 13:39:22 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-18
MD5: cc9699066953ee522ae6664f24b36087 SHA-1: 8e4c851f4656e1fd91863d11755c034a7c571785 SHA-256: c31f275047af2de973f268af22a237d32b03872bf60cf6722a105b48d1ff25fd
126 Risk Score
Tags
free-cdn-ebook-manual-lure

Malware Insights

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

The PDF file was detected as malicious by ML classifiers and ClamAV, and contains numerous embedded URLs pointing to link farms and potentially malicious content. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a pattern of using disposable hosting for link aggregation. While no scripts were explicitly extracted, the presence of embedded URLs and the nature of the heuristics suggest an attempt to redirect users to external, potentially harmful, websites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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
  • 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://leonvi.ru/wix?keyword=module+4+quiz+answers PDF link annotation
    • http://alteramaks.world/god_only_knows_choir_sheet_musicnidcx.pdfIn PDF document text
    • http://itwow.info/infection_control_today_neck_gaiters3i7y7.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4459025/normal_600505853fb5b.pdfIn PDF document text
    • http://vovpomnim.ru/pabizuxezalelurorpzf6.pdfIn PDF document text
    • http://makamar.online/442946278940o109.pdfIn PDF document text
    • http://jetavimazi.22web.org/best_love_songs_of_all_time.pdfIn PDF document text
    • http://train-home.ru/25502124913ju6ph.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4370074/normal_600c70dc7bdcb.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4366036/normal_601bee4520b53.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4368760/normal_5feda0ce07867.pdfIn PDF document text
    • http://whitetwo.space/5th_grade_math_practicexzluy.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4391636/normal_6019f22e6752f.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4497348/normal_601f1eec6c664.pdfIn PDF document text
    • http://tohld.in/fuximofejabork2bxx.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/sezewu/apple_store_games.pdfIn PDF document text
    • https://s3.amazonaws.com/xakusineba/80183015219.pdfIn PDF document text
    • http://jetetekeputesi.epizy.com/burglar_alarm_sound_effect_free.pdfIn 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d23d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD23D 5180 bytes
SHA-256: e45d6ecf54fb4690bc10d3e78e5d5d56e779d3f4f2138a7e49c8375b4825f066
font_01_sfnt_off0000e40d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE40D 10148 bytes
SHA-256: 0f650d38fe943112ed2c67220c10a7f10d7acc858ec19b9c97f122d91b2c171b

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