Malicious PDF — malware analysis report

Static analysis result for SHA-256 a81df6aedb4c2a90…

MALICIOUS

PDF

73.1 KB Created: 2021-09-25 07:20:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: fc08daa6b766cb7d9a4a899f11b03b16 SHA-1: d1897bdd543f31414757bc15da50f4dda5d8d38f SHA-256: a81df6aedb4c2a9024c27c89dd4c2eda9604706bc77103fe60b0fd17570bf2e1
166 Risk Score

Malware Insights

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

The sample was detected as malicious by ClamAV and ML classifiers, and exhibits characteristics of a phishing lure, specifically a remote-support tool pretext. The PDF contains numerous links to external PDF files hosted on various domains, suggesting it acts as a dropper or redirector. While no scripts were explicitly extracted, the PDF structure and the presence of external links indicate a likely attempt to download and execute a second-stage payload, potentially leveraging embedded JavaScript.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9940

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Remote-support tool lure high SE_REMOTE_SUPPORT_LURE
    Document instructs the user to install, open, or connect with a remote-support tool such as AnyDesk, TeamViewer, Quick Assist, or ScreenConnect — high-risk in an unsolicited document
  • 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://boston.pl/fck_pliki/file/tepejek.pdf In PDF document text
    • https://suma.ca/upload/editor/file/31819963876.pdfIn PDF document text
    • http://mientaytourist.com/uploads/files/sujipod.pdfIn PDF document text
    • http://yyfxsw.com/upload/files/348405325.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614ba453eb967---85571238433.pdfIn PDF document text
    • http://cozycornerexpress.com/uploads/files/57599252356.pdfIn PDF document text
    • https://pacientes.quiroser.com/UserFilesQUI/file/47678821863.pdfIn PDF document text
    • http://www.rosabrockenhaus.ch/ckfinder/userfiles/files/nikujopag.pdfIn PDF document text
    • https://dabanbep.tanglehadong.com/upload/files/43864889972.pdfIn PDF document text
    • http://sushibelovo.ru/files/30590334490.pdfIn PDF document text
    • http://prasongp.com/file_media/file_image/file/25085995690.pdfIn PDF document text
    • http://mannaz.pl/userfiles1/file/29113808886.pdfIn PDF document text
    • https://inprovit.com/ckfinder/userfiles/files/titokinebiren.pdfIn PDF document text
    • http://wedding-box100.com/uploads/files/202109121747138455.pdfIn PDF document text
    • http://matchedtubes.de/userfiles/file/xekosubezole.pdfIn PDF document text
    • http://st-ark.it/userfiles/files/xuvupixi.pdfIn PDF document text
    • http://nikolalepojevic5.com/multimedia/file/28825983101.pdfIn PDF document text
    • http://sugarfree-gelato.com/upload/file/72995126596.pdfIn PDF document text
    • http://kirakuramen.com/uploads/files/63164541883.pdfIn PDF document text
    • http://nb-magnet.com/upload/files/tapobusebomidigegotep.pdfIn PDF document text
    • https://www.karavanlakesfet.com/wp-content/plugins/super-forms/uploads/php/files/28f7a75245dd0aae69a8db2e179f6a0e/labetivodemidigefu.pdfIn PDF document text
    • http://flexinform.com/hirlevel/file/zawesilobizomafugegotoxi.pdfIn PDF document text
    • http://yenidenyuzlendirme.com/ckfinder/userfiles/files/47416724910.pdfIn PDF document text
    • https://totalsewa.com/userfiles/file/kemowotezurojaxi.pdfIn PDF document text
    • http://alfavit.tv/userfiles/file/wonizejipudezomez.pdfIn PDF document text
    • https://www.dooleysnaturalgas.com/ckfinder/userfiles/files/lavejatexaxagor.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/S30rS-6n6vg/uplcv?utm_term=how+to+update+play+store+on+androidPDF 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_off0000b94a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB94A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d15c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD15C 17280 bytes
SHA-256: 8e6a1b5aaa64b683ebcb5eb725922c74b1657839fda1a13c1a02345b6afa9bc0
font_02_sfnt_off0000fdd3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFDD3 10676 bytes
SHA-256: cad19aeeee0b6aaf063c685e2a0650e2a7d6a78971750a15b4f602442afcb8b6