Malicious PDF — malware analysis report

Static analysis result for SHA-256 c8c51cd955632351…

MALICIOUS

PDF

77.3 KB Created: 2021-09-21 05:53:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: c69fe0f4b3094b338170c69d3e7111b5 SHA-1: d57897957b08bef3e0d4db8e30604efc13fed1f9 SHA-256: c8c51cd955632351c17b0c198125ce7e7c62c6aaeb537e1380fd75694a2c9f1c
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as a malicious PDF by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm with numerous external URIs pointing to potentially disposable hosting, suggesting a phishing or malware distribution scheme. The PDF structure and embedded URLs are consistent with attempts to redirect users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

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 http://tinhdauvietnam.vn/upload/files/fagevegi.pdf In PDF document text
    • https://sikdercollegeofpharmacy.com/scp/ckfinder/uploads/userfiles/files/gasuvuwox.pdfIn PDF document text
    • https://netcsemege.hu/ckfinder/userfiles/files/kejol.pdfIn PDF document text
    • https://liho.cz/UserFiles/File/80373382486.pdfIn PDF document text
    • http://vinaktv.com/storage/ckfinder/files/nevimedadeliz.pdfIn PDF document text
    • http://thainightjob.com/ckfinder/userfiles/files/29519413169.pdfIn PDF document text
    • http://nobody-films.com/bpms/includes/fckeditor_uploads/userfiles/file/5084542682.pdfIn PDF document text
    • http://pc580.cn/upload_fck/file/2021-9-21/20210921050855907985.pdfIn PDF document text
    • http://klick-tipp.at/ckfinder/userfiles/publics/files/tatinirujumipekamiguzadi.pdfIn PDF document text
    • http://mayphatdienngocquang.com/media/ftp/file/jonoxas.pdfIn PDF document text
    • http://nhatminhtrading.vn/app/webroot/uploads/files/31145440303.pdfIn PDF document text
    • https://vietucmould.com/img-vietuc/files/mupasexok.pdfIn PDF document text
    • http://sahamit.net/userfiles/file/28567483976.pdfIn PDF document text
    • http://travellerisland.com/files/zesorag.pdfIn PDF document text
    • http://dj-venci.com/uploads/pages/files/zopurafe.pdfIn PDF document text
    • http://www.mab-solutions.fr/upload/file/kavigajovak.pdfIn PDF document text
    • http://koutingchina.com/upload/files/nerojimutufomifomezejifu.pdfIn PDF document text
    • http://rotarycochinharbour.org/ci/userfiles/files/mitimitilesuguf.pdfIn PDF document text
    • https://natatourism.com/userfiles/files/jokifapasoxurag.pdfIn PDF document text
    • http://bollnas.boj.se/uploads/userfiles/files/tudosulirulenudutegamukok.pdfIn PDF document text
    • https://airshow-bg.com/file/linurowejolutovijiginofo.pdfIn PDF document text
    • http://gaushalango.com/uploaded_files/userfiles/files/fupena.pdfIn PDF document text
    • http://constructionone.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161494200616f3---xalix.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/PmAiG5ZyT-k/uplcv?utm_term=emulateur+android+pour+windows+phonePDF link annotation
    • 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://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c920.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC920 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e137.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE137 10828 bytes
SHA-256: d71d045e13eeaf0c58deedd2f83d3ac47aae84c13ec0a94f48c0ae6451304d87
font_02_sfnt_off0000f9fa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9FA 17520 bytes
SHA-256: 053d8d3f0b58b7aac3a30cd97271ee2121b581598f78f810fbb39449a4b48c66

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