Malicious PDF — malware analysis report

Static analysis result for SHA-256 83b867bd986d7d4f…

MALICIOUS

PDF

90.8 KB Created: 2021-09-21 02:46:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: ad87911606657027ef49adf9c83b7ce0 SHA-1: 4158f3ff488411c1f6390c6e71ac4572cd35dc77 SHA-256: 83b867bd986d7d4f9cc2578c237c6d35ed6b156d43ed5d488601276c1880fc1b
126 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 embedded URLs, many pointing to PDFs hosted on various domains, suggesting a link farm or phishing lure. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, indicating a large number of links on disposable hosting. No scripts were extracted from this sample, but the overall structure and heuristics point to a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9947

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://booknowrentalimo.ch/userfiles/files/kasusasasudenarimozun.pdf In PDF document text
    • https://zniczekowalczyk.com/user_images/file/7448550072.pdfIn PDF document text
    • https://catwalkdogcome.com/editor_upload_image/file/nekaforosifidawanifibezo.pdfIn PDF document text
    • https://nodka.eu/ckeditor/ckfinder/userfiles/files/satetovatunivikule.pdfIn PDF document text
    • https://pottoka.info/files/galeria/files/79098463271.pdfIn PDF document text
    • http://innotack.com/userfiles/files/27519431041.pdfIn PDF document text
    • http://huiking.cn/uploads/file/040133039259.pdfIn PDF document text
    • http://eortak.com/img/fck_temp/file/kewopipuxijane.pdfIn PDF document text
    • https://vetregistr.com/ckfinder/userfiles/files/3030287781.pdfIn PDF document text
    • http://xn--9i1b14lwsg1seumdzsx.com/upload/fckeditor/file/21462685827.pdfIn PDF document text
    • https://kvzriu.org/images/file/worusoforoxen.pdfIn PDF document text
    • https://szabobuszberles.hu/files/files/xupini.pdfIn PDF document text
    • http://steelfurniturecn.com/d/files/kejaji.pdfIn PDF document text
    • http://asalsold.com/wp-content/plugins/formcraft/file-upload/server/content/files/16149070a9185f---23900645593.pdfIn PDF document text
    • http://tongshengchem.com/ckfinder/userfiles/files/85373207422.pdfIn PDF document text
    • https://edgecs.com/documents/rejowa.pdfIn PDF document text
    • http://shiraz.sk/ckfinder/userfiles/files/4738447801.pdfIn PDF document text
    • https://namhunglogistic.vn/site/files/67922249390.pdfIn PDF document text
    • http://halvani.com/wp-content/plugins/formcraft/file-upload/server/content/files/16148f0f96385a---zodediroxogadetewe.pdfIn PDF document text
    • https://excore.hu/ckfinder/userfiles/files/sanobefemaxirovapumazu.pdfIn PDF document text
    • http://kaiyudachem.com/filespath/files/20210918150103.pdfIn PDF document text
    • https://korzayithalat.com/spot/admin/fckeditor/userfiles/file/87863963474.pdfIn PDF document text
    • http://upsshop.ru/ckfinder/userfiles/files/duzedoluzoxozonilibit.pdfIn PDF document text
    • https://dangeloremodeling.com/nbloom/fckuploads/file/bepulivolebewezudazam.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/LPIa9PGmDLg/uplcv?utm_term=melhores+jogos+de+simulador+para+androidPDF 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_off0000f7dc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF7DC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010fee.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10FEE 20368 bytes
SHA-256: 720e9f3bf377df1bfc0c650e119dfba9a969b68a0ce7ba03e2f97652329c796f
font_02_sfnt_off000142f0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x142F0 10964 bytes
SHA-256: f6cafd5579438f144720bdc420da3f539493106654ca9e1e0f924c1fbe946d55