Malicious PDF — malware analysis report

Static analysis result for SHA-256 916c63367e065d85…

MALICIOUS

PDF

78.6 KB Created: 2021-07-15 15:29:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 992ec52dd7fd3010c3fe941905660848 SHA-1: fd94d12d7f2ad2f9afb4f4aaee15c93c5bbc3b2d SHA-256: 916c63367e065d8589b56d175ba2ddc38491c6f924b8c1c19c15a237b156fe29
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file was flagged by multiple heuristics and an ML classifier as malicious, with ClamAV detecting it as a phishing trojan. It contains numerous links pointing to compromised WordPress upload directories and other disposable hosting, suggesting a link farm designed to redirect users to malicious sites. The presence of embedded URLs and the nature of the heuristics indicate an attempt to exploit users through deceptive links, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

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://crewmak.ru/uplcv?utm_term=anatomy+and+physiology+fill+in+the+blank+questions PDF link annotation
    • http://jshtextile.com/UserFiles/file///sasugadesux.pdfIn PDF document text
    • https://gz-topstar.com/wp-content/plugins/super-forms/uploads/php/files/473be18520a32d1af76ed5d42348e51f/21268104378.pdfIn PDF document text
    • http://bagpack.com.np/wp-content/plugins/formcraft/file-upload/server/content/files/160a531c0367d5---sumowibabujufijudatizu.pdfIn PDF document text
    • https://www.northamericatalk.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a4d07a8d7fc---68436479593.pdfIn PDF document text
    • http://www.fsnn.se/wp-content/plugins/formcraft/file-upload/server/content/files/160777cf6dcb5d---52996116947.pdfIn PDF document text
    • http://charivne.info/images/file/99834725690.pdfIn PDF document text
    • https://www.criteriainvest.com.br/wp-content/plugins/super-forms/uploads/php/files/01erhks3cgvpvl6n18ts6adr1j/sixivuwarepu.pdfIn PDF document text
    • https://www.cdscabling.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16095b10f45cc7---6469644725.pdfIn PDF document text
    • https://t4g.nasscomfoundation.org/wp-content/plugins/super-forms/uploads/php/files/je8js6doqic0m1ic1hs99cdi16/29190381477.pdfIn PDF document text
    • http://aliancegroup.su/wp-content/plugins/formcraft/file-upload/server/content/files/16098adbf9131f---livewi.pdfIn PDF document text
    • https://powermailer.in/userfiles/file/penutulosigobarikimeme.pdfIn PDF document text
    • https://tonitomov.com/picture/file/54985988089.pdfIn PDF document text
    • http://www.risingstars.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/1608d074294916---59562113188.pdfIn PDF document text
    • http://zzliuxue.com/upfile/file///najexevejime.pdfIn PDF document text
    • http://www.zulfugar.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160906384be86d---85120279731.pdfIn PDF document text
    • http://learningkey.org/userfiles/61053540772.pdfIn PDF document text
    • https://xn--pssa17sw71b.tw/upimages/files/zafiresijemafutodu.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_off0000cdbd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCDBD 11420 bytes
SHA-256: 18ec964e2f2895e2893e62103fdbc2c4add398e1ea3aee17c63c7886923c364c
font_01_sfnt_off0000e7cc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE7CC 18604 bytes
SHA-256: 0dac88f5ace2884dcb57ced90ea0bbd53c745b4adfc383c7cb88782865d03f55
font_02_sfnt_off00011624.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11624 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1