Malicious PDF — malware analysis report

Static analysis result for SHA-256 b36544c47cfe0d64…

MALICIOUS

PDF

84.1 KB Created: 2021-02-24 10:20:29 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-07-07
MD5: 078fcb73a58a721c0b404064a971965c SHA-1: da74b3cee4e160b2c08c793ce6a24467d99ab7cc SHA-256: b36544c47cfe0d64209fa89d25e25229db1d50c347cec9cc604de56f48810445
204 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript T1203 Exploitation for Client Execution

The PDF contains a critical heuristic firing for a malicious redirector link pointing to 'https://crophysi.ru/wix?keyword=crash+bandicoot+guide+to+gems'. This URL is likely used to deliver a malicious payload or conduct phishing. The ML classifier also strongly flagged this PDF as malicious, and ClamAV detected it as 'Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0'. The document body, though heavily obfuscated, contains metadata suggesting it was generated by wkhtmltopdf, a tool often used to create malicious PDFs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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
  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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.
  • 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://crophysi.ru/wix?keyword=crash+bandicoot+guide+to+gems In PDF document text
    • http://mysteps.online/online_multiplayer_games_android_like_ludop9fbc.pdfIn PDF document text
    • https://cdn.sqhk.co/tivinarafuvu/RYHdrgc/zolati.pdfIn PDF document text
    • http://muzoc.xyz/47647665195f8jo8.pdfIn PDF document text
    • http://blaugrana.ru/barron_s_essential_words_for_the_toeflnqb2t.pdfIn PDF document text
    • http://takafebuxoz.22web.org/wasawavawazinojematerirek.pdfIn PDF document text
    • https://lexedixejorew.weebly.com/uploads/1/3/1/4/131438453/5168367.pdfIn PDF document text
    • http://kotexob.iblogger.org/zizezawizo.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4366660/normal_5fd1c5b288e80.pdfIn PDF document text
    • https://cdn.sqhk.co/kifukuvitog/KNygggd/free_new_escape_games_501_level_5.pdfIn PDF document text
    • https://cdn.sqhk.co/motulobugaji/dgfibgf/55934706216.pdfIn PDF document text
    • https://cdn.sqhk.co/jovakuki/ieVjVPE/80401217967.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/jepinebawo/78574349079.pdfIn PDF document text
    • https://s3.amazonaws.com/sumesawoxajew/easl_clinical_practice_guidelines_hcc.pdfIn PDF document text
    • http://jugututinotu.rf.gd/plataforma_lattes_atualizar_currculo.pdfIn PDF document text
    • https://s3.amazonaws.com/wifiduxezo/69777310628.pdfIn PDF document text
    • https://s3.amazonaws.com/fajixe/commando_2013_full_movie_mkv.pdfIn PDF document text
    • http://kadowuf.epizy.com/avatar_maker_anime_girl_apk.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_off000108b7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x108B7 5368 bytes
SHA-256: 53fdbc6e7fa8343e85b6c89d7a01df5fae946ea104bccf18c32a78d5870e82fe
font_01_sfnt_off00011ac3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11AC3 12480 bytes
SHA-256: 192a416403f3620fe743660b2cfa35c9ddb93dc5d7e4bf2575703cb5ae694148

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