Malicious PDF — malware analysis report

Static analysis result for SHA-256 b33831605a8776af…

MALICIOUS

PDF

77.6 KB Created: 2021-09-12 15:45:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 1a18bced529ca4f8125e968a36b55db4 SHA-1: 16ca02fc5858ef0b63a96b4989fba8cfef8b4b5d SHA-256: b33831605a8776afe3470c4f2c3635b1b9db6bcda1c8a045518f5499b89310ea
126 Risk Score

Malware Insights

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

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous embedded URLs, many of which point to PDF files hosted on potentially disposable domains, suggesting a link farm or phishing lure. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' further supports this, indicating the PDF is designed to redirect users to multiple external sites. The presence of these URLs and the overall detection profile strongly suggest an attack pattern involving redirection to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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://screen.by/images/file/51742827162.pdf In PDF document text
    • https://tarsiman.ee/files/file/24913218182.pdfIn PDF document text
    • http://nanoservice.cz/upload/file/93532077066.pdfIn PDF document text
    • https://www.reparaciondebomba.com.ar/wp-content/plugins/super-forms/uploads/php/files/2pk330qma7i2smb48g10ju2i15/71799730292.pdfIn PDF document text
    • https://siphouse96.com/wp-content/plugins/super-forms/uploads/php/files/62c3c60e5cdf98bede8aa9098882164f/44673091173.pdfIn PDF document text
    • http://bikipvuikhoedep.com/app/webroot/files/editor_upload/files/luxomikepoluv.pdfIn PDF document text
    • http://janaturismointegrato.com/uploads/file/ridovodetegozokuved.pdfIn PDF document text
    • https://frontivo.ro/userfiles/file/tapabizivejegapumaka.pdfIn PDF document text
    • http://xn--zb0bw3kv4s8mn.com/upload/fckeditor/file/fivepirukilevuxineg.pdfIn PDF document text
    • http://bonezi.morefriendship.com/upload/files/40194175200.pdfIn PDF document text
    • http://studiotecnicodama.it/userfiles/files/354940260.pdfIn PDF document text
    • https://aglogistics-bo.net/userfiles/file/napevudo.pdfIn PDF document text
    • https://dolupin.com/calisma2/files/uploads/kuludopazuxitemuved.pdfIn PDF document text
    • http://mrs724.ir/basefile/drtiketcom/files/18388787817.pdfIn PDF document text
    • http://www.dilipprabhavalkar.com/images/file/suritimesewebun.pdfIn PDF document text
    • https://kitapkapla.com/upload/ckfinder/files/naxisesenevakofad.pdfIn PDF document text
    • http://cukiernia.eu/upload/files/zaridonuvevopor.pdfIn PDF document text
    • https://studyhalltracker.com/files/file/46335294803.pdfIn PDF document text
    • http://architettosbaffo.com/userfiles/files/letukegedulijak.pdfIn PDF document text
    • http://gabortech.com/admin/file/baxuravumusarirenuga.pdfIn PDF document text
    • https://travelsafeway.com/userfiles/file/83020678686.pdfIn PDF document text
    • http://srs-budapest.hu/uploads/files/24529522822.pdfIn PDF document text
    • https://cplastik.net/data/cms/file/duwuwiwogofiwalugili.pdfIn PDF document text
    • http://galaxyjewel.cn/uploadfile/files/jogekaloreliralox.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/fzgW7-mxBc0/uplcv?utm_term=the+anatomy+of+story+pdf+downloadPDF 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_off0000c7f7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC7F7 10836 bytes
SHA-256: a8552a0e71206b3cb872bc8665157532f8c61831e92674491ec2c6c307b279d0
font_01_sfnt_off0000e0d9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE0D9 18320 bytes
SHA-256: 34b1af02fd3e3888a6a3d4afb4b79ed088de3a9dc37c18fc3bb866fd5220e784
font_02_sfnt_off00011093.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11093 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1