Malicious PDF — malware analysis report

Static analysis result for SHA-256 a7c8c2e056decd67…

MALICIOUS

PDF

73.2 KB Created: 2021-09-12 19:37:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 8ac817c604a5677d4335391a73810c0c SHA-1: efefc5fa29efaa0e618af07741fdc66a31facdce SHA-256: a7c8c2e056decd67ea08f8dd50260a60df9ac01fe65a1976ab7c0265e320d11f
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

This PDF file was flagged as malicious by a machine learning classifier and ClamAV. It contains numerous external URIs and links to compromised CMS upload storage, indicating a link farm designed to redirect users to potentially malicious content. The presence of multiple PDF_SEO_DISPOSABLE_LINK_FARM heuristics further supports the conclusion that this document is part of a scheme to manipulate search results or distribute malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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://cructi.ru/uplcv?utm_term=two+letter+words+starting+with+e PDF link annotation
    • https://billard-hauri.ch/userfiles/file/xetifujesapejus.pdfIn PDF document text
    • https://akvanova.ru/sites/default/files/15292342258.pdfIn PDF document text
    • http://skolicka.eu/foto/images/file/sugulerik.pdfIn PDF document text
    • https://lotte-ppta.com/beta/assets/file/2227274760.pdfIn PDF document text
    • https://www.yoursurveysurveyors.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/161361ba1586fe---rutozolagibij.pdfIn PDF document text
    • https://noihoithanhtuan.com/media/ftp/file/wakarafonedovunusamovezew.pdfIn PDF document text
    • http://yangs-ns.com/ckfinder/userfiles/files/20210904120036.pdfIn PDF document text
    • http://victoryelectricalsupply.com/ckfinder/userfiles/files/dijonadofojijevatumam.pdfIn PDF document text
    • http://sun-green.eu/ckfinder/userfiles/files/26018123462.pdfIn PDF document text
    • https://smartech.lv/sites/smartech/uploads/documents/files/sutaji.pdfIn PDF document text
    • http://www.madiran-cruduparadis.fr/ckfinder/userfiles/files/durevodawuk.pdfIn PDF document text
    • http://easytravel63.ru/ckfinder/userfiles/files/38894519558.pdfIn PDF document text
    • https://lostsoulsmemorialnj.org/wp-content/plugins/super-forms/uploads/php/files/7083264003737d825d793f16a1f6313b/4421210763.pdfIn PDF document text
    • https://phuketwebstudio.com/ckfinder/userfiles/files/94580537784.pdfIn PDF document text
    • http://myphamlulanjina.com/upload/files/61203117823.pdfIn PDF document text
    • http://extrastyle.ee/ckfinder/userfiles/files/xizedevodedelafokagop.pdfIn PDF document text
    • http://akvari-um.ru/userfiles/file/pobote.pdfIn PDF document text
    • https://vwb.mrv-educationservices.com/content_file/files/fegejukizakekavulu.pdfIn PDF document text
    • http://melissajacksonmd.com/wp-content/plugins/formcraft/file-upload/server/content/files/16135d891ebb24---29035533978.pdfIn PDF document text
    • http://globalsocialwlefaresummit.com/app/webroot/uploads/ckuploads/files/ranik.pdfIn PDF document text
    • http://daegyung.kr/userfiles/file/20210901131427.pdfIn PDF document text
    • http://mastervin.ru/files/file/89609821597.pdfIn PDF document text
    • http://gleb777.com/fck_upload/file/8933704571.pdfIn PDF document text
    • https://oasis-travel.ro/files/48337978173.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
stream_003_off0000e757.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0xE757 10576 bytes
SHA-256: 7ec9b45d92075d157410f87fecf2bcdf8cc7091f165f2aaa7ad53481148180a7
font_00_sfnt_off0000b9ce.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB9CE 17440 bytes
SHA-256: 3f4361ffb2a13794224da0f233a2880cc1658d955dcb2810e1649d4727914141
font_02_sfnt_off0000ff45.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF45 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1