Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef9d1fb43c27d260…

MALICIOUS

PDF

77.3 KB Created: 2021-08-18 23:59:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 66b1c27b4fe7067272f7615d2c4edb83 SHA-1: 4259df6a9b89014b17e5f7b4b50081c6496de470 SHA-256: ef9d1fb43c27d26039e37ad858ed980b44cb07e7e3f4d4fbae8710d180d5c73b
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample contains embedded JavaScript, a common technique for executing malicious code within PDFs. It also features a link farm pointing to multiple distinct hosts, many of which appear to be compromised WordPress sites. The primary URL, https://chcial.ru/uplcv, suggests a redirection mechanism likely intended to lead users to phishing pages or download further malware. The ML classifier and ClamAV detection strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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
  • 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 https://chcial.ru/uplcv?utm_term=earn+to+die+4+unblocked+77 PDF link annotation
    • https://expresstestingatl.com/wp-content/plugins/super-forms/uploads/php/files/eb520bb7921e2d0e3e3aa50c6d23a9f9/vuwaziro.pdfIn PDF document text
    • http://becro-plast.hr/wp-content/plugins/formcraft/file-upload/server/content/files/160a28a16a743f---19669058052.pdfIn PDF document text
    • http://totalfinance.ca/wp-content/plugins/formcraft/file-upload/server/content/files/16119a87acb41f---77510892182.pdfIn PDF document text
    • https://www.stjohnhomelessshelter.org/wp-content/plugins/super-forms/uploads/php/files/5b6b0f23de8d4c8815c1d81ffb8a16dc/43762671805.pdfIn PDF document text
    • https://grahampropertytax.com/wp-content/plugins/super-forms/uploads/php/files/aae0580530be10bbdf5ddb637170c1f4/kefigokaf.pdfIn PDF document text
    • http://sdds.be/userfiles/file/rivit.pdfIn PDF document text
    • http://salonlomi.pl/wp-content/plugins/formcraft/file-upload/server/content/files/16072d1672a40d---wosugasorebano.pdfIn PDF document text
    • https://www.areatransfers.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609cc121cc304---1242095176.pdfIn PDF document text
    • http://safeabortionnepal.com/userfiles/file/gopukaxe.pdfIn PDF document text
    • http://aotwresort.net/ckfinder/userfiles/files/69276994618.pdfIn PDF document text
    • http://victorylimo1.com/wp-content/plugins/formcraft/file-upload/server/content/files/1610277ebb8b3b---43024248748.pdfIn PDF document text
    • https://edu-mate.kr/_UploadFile/Images/file/78360195923.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a8fcf92ab42---8823726878.pdfIn PDF document text
    • http://labmansour.com/app/webroot/js/ckfinder/userfiles/files/80722073580.pdfIn PDF document text
    • http://lalitas-thaimassage-spa.de/wp-content/plugins/formcraft/file-upload/server/content/files/160946bb6e78f0---46671834323.pdfIn PDF document text
    • http://clinicacomciencia.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160a8022980804---watolabakopen.pdfIn PDF document text
    • https://www.hkha.org/ckfinder/userfiles/files/57705709431.pdfIn PDF document text
    • http://fujavietnam.com/images/Download/fupolugofanolisimojovab.pdfIn PDF document text
    • https://www.numberoneporthill.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160cb7c10a6a82---2507307219.pdfIn PDF document text
    • http://keletunderground.hu/images/uploaded_pics/file/56560969851.pdfIn PDF document text
    • https://investainternational.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608f7e3a5d69d---papupada.pdfIn PDF document text
    • http://www.danvillern.com/wp-content/plugins/super-forms/uploads/php/files/d6dbd36e7737f242948854eafeb91a9a/vozarepepu.pdfIn PDF document text
    • http://bergfin.se/wp-content/plugins/formcraft/file-upload/server/content/files/160c6ffe0b7cc4---82132503108.pdfIn PDF document text
    • http://bptramptour.pl/files/file/94017128229.pdfIn PDF document text
    • https://kakvkusno26.ru/wp-content/plugins/super-forms/uploads/php/files/53f007315fcefa6f2cc172deec51a957/dager.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_off0000ca8f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCA8F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e2a6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE2A6 10640 bytes
SHA-256: 3a708c181c0d679885ac4af7ad75b036b3d8260e844a11964f5212c60c7ad5a8
font_02_sfnt_off0000fb26.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB26 17100 bytes
SHA-256: c7c44ec69688b69632fc61989fe1ffb73249f16d7fbbfdf19a1005c3cb2507da