Malicious PDF — malware analysis report

Static analysis result for SHA-256 c91c214763c483ac…

MALICIOUS

PDF

89.1 KB Created: 2021-06-28 21:25:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 19c1f31af0109f9d2fb6db969121d5c0 SHA-1: e3bbce3625c5df2e010c21ad1d34f85c4a73b2ae SHA-256: c91c214763c483ac5519f278d7fac44a03bb4d6c4bdce90eaa7e33a691750b93
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was identified as malicious by ML classifiers and ClamAV, indicating a phishing or trojan threat. It functions as a link farm, with numerous URLs pointing to compromised WordPress upload directories, likely serving as a distribution point for further malicious payloads. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user consumption but rather as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

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
  • 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.
  • 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://ventana-sur.com/wp-content/plugins/formcraft/file-upload/server/content/files/160941924e6c32.pdf In PDF document text
    • https://www.saenger-ohg.de/wp-content/plugins/formcraft/file-upload/server/content/files/160a15ab7e3f4f---terovovobezivu.pdfIn PDF document text
    • http://aliceinformaticasrl.com/user/pages/15833914672.pdfIn PDF document text
    • https://uaqbakery.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a08d1f8bd81---vevezam.pdfIn PDF document text
    • http://boulderdivorcelaw.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607df83f0275e---gemuvewemu.pdfIn PDF document text
    • https://vandolderskb.com/images/usr/12786154985.pdfIn PDF document text
    • http://kaufdeinauto.de/wp-content/plugins/formcraft/file-upload/server/content/files/160bf196d3c0d2---duzirobofoxasuzamug.pdfIn PDF document text
    • https://www.marvistasales.com/wp-content/plugins/super-forms/uploads/php/files/ab50c367f6c084a71fd82f9093dead2c/bekufuna.pdfIn PDF document text
    • http://www.canadavisaservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608a78a26abce---85466614564.pdfIn PDF document text
    • http://kassa.pl/userfiles/file/mutibifiv.pdfIn PDF document text
    • http://longvu.vn/Images_upload/files/33191126069.pdfIn PDF document text
    • http://www.petersmetalstitching.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/1609cfc7c916e5---baxuwakafosodiz.pdfIn PDF document text
    • http://carnavaldemarbella.com/Senegal_5/Content/files/userfiles/file/vosaxisurezanibifeke.pdfIn PDF document text
    • https://fiambreszav.com/wp-content/plugins/super-forms/uploads/php/files/91bd7472ce32b515033b02e3050dc0f8/34644416743.pdfIn PDF document text
    • https://www.qlsny.com/wp-content/plugins/super-forms/uploads/php/files/7b3e122a569a3d907f925b8ea22fe6fa/92860800634.pdfIn PDF document text
    • https://www.aserspa.net/wp-content/plugins/super-forms/uploads/php/files/aedsoa4uqcrpmsehe2839j09hn/fiwisutumeluluse.pdfIn PDF document text
    • http://adamlegal.com/userfiles/file/beropigufebukopurewevov.pdfIn PDF document text
    • https://shining4u.com/wp-content/plugins/super-forms/uploads/php/files/ff0d166caf37efe2db3d0ba3582a0fe6/79281091807.pdfIn PDF document text
    • https://www.themeshcowork.com/wp-content/plugins/super-forms/uploads/php/files/29b2af45b56cbd663423e4d5cd2d3479/23717424932.pdfIn PDF document text
    • http://www.kinoimaging.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1608fc1be96d23---89415866169.pdfIn PDF document text
    • http://0-50.ru/userfiles/file/33447474874.pdfIn PDF document text
    • http://investin-khj.ir/ckfinder/userfiles/files/xadidepogirupuguwiresa.pdfIn PDF document text
    • http://www.hkwebdesign.com.hk/wp-content/plugins/formcraft/file-upload/server/content/files/1607a765d55d70---xemuwiginolovukigusiv.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/A3Ryygt5BCM/uplcv?utm_term=how+many+calories+burned+in+30+push+upsPDF 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_off0000f724.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF724 11408 bytes
SHA-256: 455efd4795ad01a867a491ffe349117be077d271e0779fdcc49d497aecbc4266
font_01_sfnt_off000111a2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x111A2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000129b4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x129B4 17208 bytes
SHA-256: c6834a38e55bab3e4c14e329017ac1228d539ca2028e68c598baf6799c8f36b2

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