Malicious PDF — malware analysis report

Static analysis result for SHA-256 b1ef78e2e606e8b1…

MALICIOUS

PDF

83.2 KB Created: 2021-09-12 01:05:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 65e7acaf1ac6753888f402b74d4e463b SHA-1: cd63fc47ec2525def27949a5c3cdcf8cfe45eaf6 SHA-256: b1ef78e2e606e8b1da30d525ad932f4374798e05865b28f6f50498e28e3faf20
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file flagged by ClamAV as Pdf.Phishing.Trojan and by an ML classifier as malicious. It contains numerous links to external PDF files hosted on various domains, many of which are identified as a link farm on disposable hosting. One high-severity heuristic specifically points to a PDF link to an algorithmically-generated URL, suggesting a pattern of distributing further malicious content. While no scripts were explicitly extracted, the PDF structure and numerous external links indicate an attempt to redirect users to malicious resources, likely for phishing or malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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 link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://veiligheidssloten.nl/ckfinder/userfiles/files/4907720413.pdf
    • https://careerexpo.alljobsinliberia.com/ckfinder/userfiles/files/nufez.pdf
    • http://fujieshubao.com/zk/UploadFile/file/2021090301130473499.pdf
    • https://actsonics.com/uploads/files/202108312121239101.pdf
    • http://myepres.com/HotelEstimator/userfiles/file/minosivufivofus.pdf
    • http://levant-tekstil.com/other_files/File/besej.pdf
    • https://www.andyselfstorage.co.uk/wp-content/plugins/super-forms/uploads/php/files/2qtuu5knumau1q1f567g4jjsm0/34348303404.pdf
    • http://longruiglass.com/ckfinder/userfiles/files/20210909_152004.pdf
    • http://studionegro.net/userfiles/files/12987798054.pdf
    • http://baove24h.org/upload/files/40560933384.pdf
    • http://yangpupark.com/uploadfile/files/79561295102.pdf
    • http://paletydozahrady.cz/ckfinder/userfiles/files/maratazijopalaj.pdf
    • http://physio-praxismitte.de/userfiles/loweluzawujadobovimaw.pdf
    • https://eagle-aviation.com/userfiles/files/rulolekubalodenaxa.pdf
    • https://sayurhijau.com/contents/files/kevuwasogobakurudizufim.pdf
    • http://bharatandcompany.in/ckfinder/userfiles/files/fawakifugorixali.pdf
    • http://lucidarepavimentimarmogenovaealessandria.it/userfiles/files/10508255873.pdf
    • http://michaelwilliamslaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/sizikudipubovodorovut.pdf
    • http://movediary.com/userfiles/file/juzerurojuduvowu.pdf
    • https://olterus.org/contents/files/tozudumejevakogozo.pdf
    • https://himalayanespresso.com/espresso_ckfinder/userfiles/files/49051675770.pdf
    • https://perfecthospitals.org/FCKeditor/file/88264372807.pdf
    • https://susta.vn/userfiles/file/39361617220.pdf
    • http://haiannweb.com/uploads/files/xabafufun.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=justice+league+snyder+cut+yts+download
    • 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://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000dc37.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0xDC37 16792 bytes
font_01_sfnt_off0000f44e.bin
f983bf36fed99bd6184b59ff5be6a86eeb6b45e682680aea2e56f1018c43ec6e		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF44E 10836 bytes
font_02_sfnt_off00010d5f.bin
dbf11d38213f91b33ddb6380a2bc628fefea4c16a056b8880d9336729bbe0f77		 pdf-font-stream PDF embedded font (sfnt) at offset 0x10D5F 19196 bytes

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