Malicious PDF — malware analysis report

Static analysis result for SHA-256 f3a3e2b8fbf3b17c…

MALICIOUS

PDF

84.5 KB Created: 2021-09-20 09:14:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: c9185f8c08187d23eda504acafea9c27 SHA-1: 3c1f58b596f34378181c03da0f7eb4dfb18ce6b7 SHA-256: f3a3e2b8fbf3b17c5708fbe82d40b624e521024fd199b10a4bd12a4b6bd6d01f
134 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected as malicious by ClamAV and an ML classifier, with critical and high severity firings respectively. It contains embedded JavaScript, which is a common technique for executing malicious code within PDFs. The PDF also acts as a link farm, pointing to numerous external PDF files, suggesting a distribution or redirection mechanism. The primary attack pattern involves leveraging the embedded JavaScript to likely download and execute a second-stage payload or redirect the user to a malicious site.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

Heuristics 6

  • 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.
  • 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.
  • 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://xedulichhaiphong.vn/images/news/files/fixezezevejiwoxebutu.pdf In PDF document text
    • http://lecieldesandes.fr/ckfinder/userfiles/files/11096064019.pdfIn PDF document text
    • http://fkjz.cn/upload/files/2021/09/202109071335162287.pdfIn PDF document text
    • https://artistaone.co/userfiles/files/18258629693.pdfIn PDF document text
    • http://balaton.varosom.hu/userfiles/files/4007276675.pdfIn PDF document text
    • https://jordan.si/dokumenti/file/12232322122.pdfIn PDF document text
    • http://seatraderhk.com/userfiles/12195638895.pdfIn PDF document text
    • https://divorcioconsensual.com.br/wp-content/plugins/super-forms/uploads/php/files/07990dd2c293e586148e56ff8b1836c8/25208975340.pdfIn PDF document text
    • http://wksystems.net/HotelEstimator/userfiles/file/pinuvijazata.pdfIn PDF document text
    • https://bishopsalamatkhokhar.org/userfiles/file/64402678086.pdfIn PDF document text
    • https://clubforeducation.com/FCKeditor/userfiles/file/82785395861.pdfIn PDF document text
    • http://www.syrahresources.com.au/application/third_party/ckfinder/userfiles/files/80482355857.pdfIn PDF document text
    • http://nhagiatxanh.com/public/default/ckeditor/files/kaximomuvokabaruz.pdfIn PDF document text
    • http://volvo-cars.jp/js/upload/files/julofu.pdfIn PDF document text
    • https://sunnyvale.com/wysiwygfiles/file/juvofotikuvezi.pdfIn PDF document text
    • http://driver-jazda.pl/upload/file/lalimegaxekar.pdfIn PDF document text
    • http://masterref.ru/editorfiles/file/zelunilovovilirukepe.pdfIn PDF document text
    • http://casadiriposomarsala.it/userfiles/files/duduvowevuzubejupetamipi.pdfIn PDF document text
    • http://megaprestige.ru/uploads/files/2635498394.pdfIn PDF document text
    • https://www.dazzlingdecor.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16138e332296d3---42372668158.pdfIn PDF document text
    • http://infinity-pro.ru/userfiles/file/86604912963.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BvfzZFkJO3s/uplcv?utm_term=how+to+find+blocked+numbers+on+androidPDF link annotation
    • http://s292376414.onlinehome.fr/datas/imgmail/file/nidesavolesarox.pdfIn PDF document text
    • 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_off0000e3b2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE3B2 11048 bytes
SHA-256: 57fa0722839d08b8a3cbddafccd269932793cce73c8b1a8ba21228fb58617c85
font_01_sfnt_off0000fd64.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFD64 18212 bytes
SHA-256: ae52af8c921e7f12abe1b116d0fef0bb3ef362095fae0b54a1652a6dbff4be7e
font_02_sfnt_off00012c54.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12C54 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1