Malicious PDF — malware analysis report

Static analysis result for SHA-256 23cfea9c8d343920…

MALICIOUS

PDF

72.4 KB Created: 2021-09-18 22:14:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: 6f23b22898709869ab669ba53e5c285e SHA-1: afaa64acb9879b72199a50e1a352b90d162fa933 SHA-256: 23cfea9c8d34392058977a64ec4908b8bfdb88e145155e8e27cd3113b0ced034
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. The heuristics indicate it functions as a link farm, with numerous embedded URLs pointing to other PDF files hosted on various domains. While no scripts were explicitly extracted, the PDF structure and the nature of the embedded links suggest an attempt to manipulate search engine results or distribute further malicious content, potentially via embedded JavaScript.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9840

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 http://rebizplus.com/userfiles/file/29069489332.pdf In PDF document text
    • http://masterkontroll.hu/ckfinder/userfiles/files/53811684415.pdfIn PDF document text
    • https://hmjrgoldhockey.org/wp-content/plugins/super-forms/uploads/php/files/61fcae9cb35c47e2ef0a9342ef1aeffa/61115026171.pdfIn PDF document text
    • http://asiancfea.org/userfiles/file/53402936002.pdfIn PDF document text
    • http://morard-mcf.fr/data/Files/64797236135.pdfIn PDF document text
    • http://bascobrunswick.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1613d329e7dfe8---29453078619.pdfIn PDF document text
    • https://pamukoglu.com/userfiles/file/tipukafapujulata.pdfIn PDF document text
    • http://casavacanzesanvito.eu/userfiles/files/luregixomexiralaza.pdfIn PDF document text
    • http://namuvaldymas.lt/userfiles/file/38273444231.pdfIn PDF document text
    • http://salon-urody-bellis.pl/images/file/tobet.pdfIn PDF document text
    • https://ingatlansos.hu/images/userfiles/file/83622852379.pdfIn PDF document text
    • http://pscworld.eu/ckfinder/userfiles/files/8711698862.pdfIn PDF document text
    • http://aorganboys.handyfriendship.com/upload/files/72899496985.pdfIn PDF document text
    • http://absolutelyneon.com/userfiles/file/14214954722.pdfIn PDF document text
    • http://ahzgbh.news-read.com/upload/files/xofuwalemezadugeni.pdfIn PDF document text
    • https://mediaget.ru/userfiles/files/96922180349.pdfIn PDF document text
    • https://homestayhoian.vn/uploads/image/files/guvifolotukag.pdfIn PDF document text
    • http://bezpiecznamlodosc.org/files/file/bedoparazozanivozaw.pdfIn PDF document text
    • http://kossuthdigisuli.hu/userfiles/file/dekone.pdfIn PDF document text
    • https://pracowniatechart.pl/fckpliki/file/40751803047.pdfIn PDF document text
    • http://landonintergroup.com/ckfinder/userfiles/files/23402415226.pdfIn PDF document text
    • https://phunhai.net/upload/files/tejefut.pdfIn PDF document text
    • http://gimhaejazz.com/fckeditor/userfiles/image/xujitiwobazujopeliju.pdfIn PDF document text
    • http://kxxbs.com/uploadfiles/file/a/64720325860.pdfIn PDF document text
    • http://www.guus.edu.mn/ckfinder/userfiles/files/42971976967.pdfIn PDF document text
    • http://solo-reisen.com/media/images/file/jesosajaduvugugekuw.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/3vuEKuznOb8/uplcv?utm_term=how+to+download+android+apps+to+computerPDF 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_off0000b8f0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB8F0 16472 bytes
SHA-256: a78fdd3c122667b5c7cd60bb2d6e37bad4c2764e8f25f2f2ed4eef951373fee2
font_01_sfnt_off0000e2e8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE2E8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000faff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFAFF 10852 bytes
SHA-256: f401fe6ef69eeabb93c2a36a207e8eb5114e3e269acc3afd7cb4ee039410eba5