Malicious PDF — malware analysis report

Static analysis result for SHA-256 61b773ce977505c9…

MALICIOUS

PDF

84.2 KB Created: 2021-10-07 10:13:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-23
MD5: 94b1fdafc36f824c3d39d44601a9c52d SHA-1: 63b20ed65e556faf2a287225dfc8fe84d68b1662 SHA-256: 61b773ce977505c9d2a44d5bba1e5b800ecbe238f5bf21925ca6312e78484928
142 Risk Score

Malware Insights

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

The sample is identified as malicious by ClamAV and an ML classifier, with heuristics indicating embedded JavaScript and external URIs. The embedded JavaScript is likely used to download and execute a second-stage payload, as suggested by the 'ML_NYX_PDF_MALICIOUS' and 'CLAMAV_DETECTION' firings. The presence of numerous unknown URLs, some hosted on potentially disposable domains, further supports a phishing or malicious content delivery scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://www.sas.edu.mn/ckfinder/userfiles/files/nulavuwolofuxaji.pdf In PDF document text
    • https://kozhikodedeaf.org/admin/my_files/file/pasifawaruzelonikurureg.pdfIn PDF document text
    • http://nickels.design/ckfinder/userfiles/files/wisozorasaleme.pdfIn PDF document text
    • http://naturestuff.nl/siteimages/file/sejod.pdfIn PDF document text
    • https://www.shamshabaddiocese.org/files/js/ckfinder/userfiles/files/bufupelozakila.pdfIn PDF document text
    • http://daiichibus.vn/uploads/news_file/kujoludivenovofaxiduteje.pdfIn PDF document text
    • http://hotechike.com/files/files/xakixudedetune.pdfIn PDF document text
    • http://beerskiboot.de/img/upload/file/difuxupezeforuwimo.pdfIn PDF document text
    • https://dobre-akce.cz/media/files/file/95760078842.pdfIn PDF document text
    • http://abwingstop.com/uploads/files/38233541607.pdfIn PDF document text
    • https://perkunasstudio.com/uploads/files/202109192243342246.pdfIn PDF document text
    • http://pfmconsulting.org/survey/userfiles/files/62266301385.pdfIn PDF document text
    • https://ciar.vn/uploads/image/files/20284171669.pdfIn PDF document text
    • https://bunyaminerdemir.com/resimler/files/56416144958.pdfIn PDF document text
    • http://victoryelectricalsupply.com/ckfinder/userfiles/files/17413645010.pdfIn PDF document text
    • http://yoron.net/up/files/divawedakarokifozib.pdfIn PDF document text
    • http://bridgestone-ice-cruiser-7000.ru/ckfinder/userfiles/files/bepono.pdfIn PDF document text
    • http://fruhmann-elektrotechnik.at/66129675609.pdfIn PDF document text
    • https://kp-bs.ru/upload/files/nalejedateganuxumama.pdfIn PDF document text
    • http://yogathoitrang.com/quangbasanpham/app/webroot/upload/image/files/bezoj.pdfIn PDF document text
    • http://veitali.com/upload/files/58052773207.pdfIn PDF document text
    • http://kommunikator.nu/demo/userfiles/file///66891059555.pdfIn PDF document text
    • http://heyumpnd.com/userfiles/file///20473814950.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=pdf+to+word+with+formatting+onlinePDF 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_off0000e51a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE51A 17788 bytes
SHA-256: 3ef94a307e049e88791383e506035ad54059c2d068f6c1a1975e7276170791d0
font_01_sfnt_off0001131a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1131A 10720 bytes
SHA-256: d2b56eed35b58d7d0fd98181819f2e494a664639ee7c14716f3b48c455e74b5e
font_02_sfnt_off00012b59.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12B59 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1