Malicious PDF — malware analysis report

Static analysis result for SHA-256 87ef5c06e6b736af…

MALICIOUS

PDF

80.0 KB Created: 2021-09-11 06:42:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 21086409007eb5bb7753e16c2274c536 SHA-1: 0b9a4706f028e2aa519ab1ecbcbe778c16e3250c SHA-256: 87ef5c06e6b736afa2b7cb6e526d3bb448e33966dfa3967f07ad6eb3fa60d261
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous external URIs, including one that appears to be a link farm on disposable hosting, suggesting a phishing or malware distribution lure. The PDF structure and embedded content, though heavily obfuscated, are consistent with attempts to redirect users to malicious websites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 5

  • 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.
  • 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://laborke.ru/uplcv?utm_term=understanding+chess+tactics+pdf PDF link annotation
    • https://dlt-nkp.com/fileupload/file/5179770440.pdfIn PDF document text
    • https://a1-recruitment.fr/v2011/Files/fck_upload/file/43928592988.pdfIn PDF document text
    • http://www.galiantsolutions.com/emailimages/file/norupowi.pdfIn PDF document text
    • https://red-adlay.com/upload/files/29312203349.pdfIn PDF document text
    • http://gz-theoutfit.com/UploadFiles/FCKeditor/20210911042254.pdfIn PDF document text
    • https://callmarkinvestments.com/callmark/files/bimur.pdfIn PDF document text
    • http://cottoneauto.it/userfiles/files/29141438671.pdfIn PDF document text
    • http://virus-safe-zone.com/ckupload/files/vevobijusozelifimusa.pdfIn PDF document text
    • https://hongmao.tw/uploads/files/202109030246063292.pdfIn PDF document text
    • http://pm-property.pl/userfiles/file/donisix.pdfIn PDF document text
    • https://ceccarbotosani.ro/userfiles/file/muzabipezikipezupefufati.pdfIn PDF document text
    • http://kmsenior.org/file/files/fidetope.pdfIn PDF document text
    • https://sentralperdana.com/file/wovutenezupigadewi.pdfIn PDF document text
    • http://imailbox.nl/images/uploadedimages/file/9279373220.pdfIn PDF document text
    • https://spirit-legend-enterprises.com/webroot/editor-uploads/files/basijazonopeja.pdfIn PDF document text
    • https://auf.vn/wp-content/plugins/super-forms/uploads/php/files/mura0f80nevndg7ice4dcj42c7/23554982660.pdfIn PDF document text
    • http://osc-pribor.ru/products_pictures/file/73394129499.pdfIn PDF document text
    • https://kalimati.in/userfiles/file/lutigo.pdfIn PDF document text
    • https://jesssmithtri.com/jesssmith/ckfinder/userfiles/files/95510696923.pdfIn PDF document text
    • http://drumlockingclamp.com/FCK_Editor_Images/files/40959236560.pdfIn PDF document text
    • https://sketchup360.vn/wp-content/plugins/super-forms/uploads/php/files/khr5tv2se9rck2orcvao1gbb1k/tusulirekixiga.pdfIn PDF document text
    • http://magendans.com/imagefiles/file/22725281663.pdfIn PDF document text
    • http://flexinform.com/hirlevel/file/78950550308.pdfIn PDF document text
    • http://2018.letnifestiwal.pl/ckfinder/userfiles/files/xibiwagigive.pdfIn PDF document text
    • http://vip-cond.ru/userfiles/file/wojozujogepekiwab.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_off0000d720.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD720 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ef37.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF37 10740 bytes
SHA-256: 1654cb19af12f6b3e140cda6fe9afd839ffed4b2dafb29d58029422bca9d711f
font_02_sfnt_off00010798.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10798 16508 bytes
SHA-256: 1a76ddf8a0f9506a00d35c297683a11920450372e1ee6bcd569068829d0908f0