Malicious PDF — malware analysis report

Static analysis result for SHA-256 71c93e8e014455c1…

MALICIOUS

PDF

86.8 KB Created: 2021-08-08 19:28:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: e68de802d1c18b07e32bbd048fa766a2 SHA-1: 4596cb685c0c93c98f0b156d2cb41860f1fcfb8e SHA-256: 71c93e8e014455c148ff52cd277692c4715215aae401113b420aac9b124a3c34
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript, which is a common technique for executing malicious code. Several heuristics indicate that the document hosts a link farm pointing to potentially compromised WordPress upload storage and other disposable hosting, suggesting an attempt to distribute malicious files or redirect users to phishing pages. The ClamAV detection as 'Pdf.Phishing.Trojan' further supports the malicious nature of this file.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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 http://www.holzbau-hoelzl.at/wp-content/plugins/formcraft/file-upload/server/content/files/1609863430ea37---73254612637.pdf In PDF document text
    • http://bluefield1966.com/clients/26642/File/kagobureku.pdfIn PDF document text
    • https://studiogreenwich.ru/wp-content/plugins/super-forms/uploads/php/files/b234c8017d9dbf19f93cd81f6f85efcc/kexunape.pdfIn PDF document text
    • https://www.lowdoc-loans.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160ae347b5dbdc---845203091.pdfIn PDF document text
    • https://www.saenger-ohg.de/wp-content/plugins/formcraft/file-upload/server/content/files/16080ab0e5abb5---wijota.pdfIn PDF document text
    • https://flyfinz.com/userfiles/files/75264679466.pdfIn PDF document text
    • http://www.martiusstaden.org.br/js/ckfinder/userfiles/files/73681915396.pdfIn PDF document text
    • http://visualpaint.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d8ba47d053b---11101425602.pdfIn PDF document text
    • http://tnslib.net/userfiles/files/juwexuputefarixobox.pdfIn PDF document text
    • https://premiumtrade.ro/ckfinder/userfiles/files/baxesazuwow.pdfIn PDF document text
    • https://www.novet.de/wp-content/plugins/formcraft/file-upload/server/content/files/160a9070024a80---tafukexebelumalulex.pdfIn PDF document text
    • http://vienkiemis.lt/app/webroot/uploads/userfiles/files/nuledukewejakuzo.pdfIn PDF document text
    • http://adamslakeband.org/userfiles/file/12209408466.pdfIn PDF document text
    • https://xo-sound.ru/userfiles/file/34594984830.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/PmAiG5ZyT-k/uplcv?utm_term=resignation+letter+sample+format+for+teachersPDF 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_off0000ee7a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE7A 16808 bytes
SHA-256: 20ac1d6e860d551c104bb25b3db553e7e68b7bbb1db665e6f894804bd559a8aa
font_01_sfnt_off000119e2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x119E2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000131f9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x131F9 10972 bytes
SHA-256: 3c3eec921c31a6cdc7f3b0504f79fbd3f9d122c6beb0d1443654a635c5d15f09