Malicious PDF — malware analysis report

Static analysis result for SHA-256 21c116a5bce23be0…

MALICIOUS

PDF

86.9 KB Created: 2021-09-18 19:18:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 8f5ab7f6bdb5d915a0ef5539e5677509 SHA-1: 11317720aa8d05714d3f54642693b1dc5e1240ec SHA-256: 21c116a5bce23be057933c214d94df8c4837f87195a1dd2177c90a14b902b737
126 Risk Score

Malware Insights

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

The sample was flagged by ClamAV as a phishing trojan and a machine learning classifier indicated a high probability of maliciousness. The PDF contains numerous embedded URLs, many pointing to disposable domains, and is identified as a link farm. This suggests the primary purpose is to redirect users to potentially malicious content or for SEO manipulation.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

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://gencshow.com/upload/ckfinder/files/zewunin.pdf In PDF document text
    • http://manhchenang.vn/webroot/img/files/7231330706.pdfIn PDF document text
    • http://ed-union05.ru/files/file/kidasapigomuwuzibogivexu.pdfIn PDF document text
    • http://veronicanealhome.com/wp-content/plugins/formcraft/file-upload/server/content/files/2/1612f06716d054---67934209483.pdfIn PDF document text
    • https://techson-cctv.com/upload/file/serixazovazexigubumi.pdfIn PDF document text
    • http://udokutscher.de/gfx/userfiles/files/podesadulajer.pdfIn PDF document text
    • http://armanetti.com/images/21405617791.pdfIn PDF document text
    • http://laarakkers.com/ckfinder/userfiles/files/36653881867.pdfIn PDF document text
    • http://stellarp.com/userfiles/file/bekesavumiwebagi.pdfIn PDF document text
    • http://manvilastrust-org.bvirani.com/ckfinder/userfiles/files/97974199118.pdfIn PDF document text
    • https://archielectronics.com/userfiles/files/jizotazurivi.pdfIn PDF document text
    • https://stayinbranson.com/ckfinder/triplebuserfiles/file/popofa.pdfIn PDF document text
    • https://nevjegyzek.eu/uploads/file/topajimadamitexasiki.pdfIn PDF document text
    • http://tv-sat.cz/userfiles/file/40256639390.pdfIn PDF document text
    • http://safarekhoob.ir/basefile/safarekhoobir/files/niwenukim.pdfIn PDF document text
    • http://dgjinhak.kr/DATA/upload/files/202109140320116342.pdfIn PDF document text
    • http://www.juthamasclinic.com/upload/finder/files/70991298046.pdfIn PDF document text
    • https://nepalihemp.com/ckfinder/userfiles/files/72820371253.pdfIn PDF document text
    • http://ekhoron21.mn/uploads/files/88235063854.pdfIn PDF document text
    • https://weldingportal.it/userfiles/file/17030447047.pdfIn PDF document text
    • https://backcountryplayground.com/wp-content/plugins/super-forms/uploads/php/files/a73451d8d92f3837eadf20fa847bc7f8/kidakijumuzorapef.pdfIn PDF document text
    • http://arc-en-cielproduce.com/ckfinder/userfiles/files/24809927289.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/DOqCt-cVA4I/uplcv?utm_term=how+to+create+menu+in+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_off0000ec9a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC9A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off000104b1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x104B1 10492 bytes
SHA-256: f5c27745cc02890e742719abfdd55518d298de8c003af3c370bee7e0555e2a49
font_02_sfnt_off00011c80.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11C80 18700 bytes
SHA-256: 1ff2db8e7961dda1514ee42d88ea04fa9dab144111013f30768866d2ff0b92fe