Malicious PDF — malware analysis report

Static analysis result for SHA-256 638880e542fda0ac…

MALICIOUS

PDF

77.2 KB Created: 2021-09-21 11:26:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 4b253d0c46e8918ccb7c635fd05940c4 SHA-1: 53e1ea723e7704ee298a30b4db985700ab2c61c7 SHA-256: 638880e542fda0acb644eaefea96a4c32021640c11c2633b4ba7ced9fad81281
134 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was identified as malicious by ML classifiers and ClamAV, with a critical heuristic firing for PDF_JS indicating embedded JavaScript. This JavaScript is likely responsible for redirecting the user to external URLs, as suggested by the PDF_URI and PDF_SEO_DISPOSABLE_LINK_FARM heuristics. The presence of numerous external links, many on potentially disposable domains, further supports a phishing or malware distribution vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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
  • 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://efficientinfocomm.com/ckfinder/userfiles/files/buwuxizasadaxaja.pdf In PDF document text
    • https://biharlokmanch.org/userfiles/file/15915721519.pdfIn PDF document text
    • https://eletvital.hu/uploads/files/52056035898.pdfIn PDF document text
    • https://cupanghitam.com/contents/files/kijawiveporogujafo.pdfIn PDF document text
    • https://madame-tina.com/ckfinder/userfiles/files/vujekorusevoxujuxoj.pdfIn PDF document text
    • https://bbensonmft.com/wp-content/plugins/super-forms/uploads/php/files/ec226b9813e0b2433bfe884e1ca3c1d4/44550275754.pdfIn PDF document text
    • http://diversecityuk.com/userfiles/file/65051098918.pdfIn PDF document text
    • http://td-mg.ru/uploads/files/beduredivojavoduzixunet.pdfIn PDF document text
    • https://antoinepanau.com/wp-content/plugins/super-forms/uploads/php/files/4cb516458706178c8cf6c69e4def01d6/54676280129.pdfIn PDF document text
    • http://mweb.cz/images/file/fepovoperatog.pdfIn PDF document text
    • http://adbrf.com/files/fckeditor/file/606488836613f41e8bfded.pdfIn PDF document text
    • http://vaynhe.com/upload/files/43989909688.pdfIn PDF document text
    • https://nepalfinepashmina.com/userfiles/file/jikapudaregobirokefe.pdfIn PDF document text
    • http://langmoon.jp/js/upload/files/xizimuvujuvebitosogo.pdfIn PDF document text
    • https://halkum.rs/files/bavazexujimevobezoxigov.pdfIn PDF document text
    • http://musicandyouapp.com/webupload/editorimg/files/disazakedenoxowizewaxalap.pdfIn PDF document text
    • http://aptekarynek.pl/zdjecia/fck/file/59499195640.pdfIn PDF document text
    • https://aecvfcom.nrgence.com/upload/userfiles/files/23760817104.pdfIn PDF document text
    • http://www.srijonihealinghome.com/fckimages/file/lerozekuniwax.pdfIn PDF document text
    • http://biznesfishki.ru/files/userfiles/files/rasokafokonubalesetik.pdfIn PDF document text
    • http://jj-metals.com/userfiles/file/2021090423192473499.pdfIn PDF document text
    • http://milwaukee.center/userfiles/file/20458082753.pdfIn PDF document text
    • http://resortvillairene.it/userfiles/files/leburufapejojujigazebe.pdfIn PDF document text
    • http://netisiletisim.com/guvennet/resimlerfiles/kinepi.pdfIn PDF document text
    • http://bosch-elektronarzedzia.pl/catalog/file/ziziraz.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1xuhb7AK25c/uplcv?utm_term=mod+photo+labPDF 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_off0000cd17.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCD17 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e529.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE529 17028 bytes
SHA-256: 4a7ecc7c9760d938917063ac008075876952d661eb1d0d69724fddca7ad1326b
font_02_sfnt_off00011158.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11158 10024 bytes
SHA-256: e86fcc219cb7aae443fcb4ee8d761de60161c86c2e602485f6d9c90545e81ad4