Malicious PDF — malware analysis report

Static analysis result for SHA-256 6639cc05b17735d0…

MALICIOUS

PDF

85.8 KB Created: 2021-09-22 23:53:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 04855906d05ae6d84fc6565849f49152 SHA-1: a2ab3b5729fe41e687724e46567a509bb1b9e929 SHA-256: 6639cc05b17735d069c44f0925d8921aa46e8b21f429c4d1eb2500eb0da15f74
146 Risk Score

Malware Insights

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

The sample was flagged by multiple heuristics, including a high-confidence ML classifier and ClamAV, for containing a malformed exploit stream. The PDF also functions as a link farm, with numerous embedded URLs pointing to potentially malicious content. The presence of an exploit stream indicates an attempt to execute code upon opening the document.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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://termosystem.pl/userfiles/file/xetitexirasawulolurigale.pdf In PDF document text
    • http://kmjmt.com/news/upload/file/210913095246911138alwfmh.pdfIn PDF document text
    • http://vector-mebel.ru/uploads/files/3568129477.pdfIn PDF document text
    • https://ksi-system.pl/editorfiles/file/xedejumewegegufazekamokub.pdfIn PDF document text
    • http://vattuxaydunghl.com/userfiles/file/subowubadadanepasigew.pdfIn PDF document text
    • http://lacasedescaraibes.fr/file/zegoxodenosigovapomelok.pdfIn PDF document text
    • http://ekstelekom.com/userfiles/file/10557055357.pdfIn PDF document text
    • http://pocatellocampfire.com/wp-content/plugins/super-forms/uploads/php/files/ntfk9j0u6ol7eolrkaimhest34/84089808743.pdfIn PDF document text
    • https://gea99.com/ckfinder/userfiles/files/30269593545.pdfIn PDF document text
    • http://dlastudenta.org/Upload/file/6143954684.pdfIn PDF document text
    • http://evo-models.com/uploads/userfiles/files/gutofidokewuwa.pdfIn PDF document text
    • http://protezas.lt/i/File/10418647821.pdfIn PDF document text
    • http://maradonasalud.com.ar/ckeditor/ckfinder/userfiles/files/sikowuwiwepolarizabulub.pdfIn PDF document text
    • http://topnotchimports.com/ckfinder/userfiles/files/pejenivugusisizirojenoze.pdfIn PDF document text
    • http://maremania.net/img_pagine/file/sidola.pdfIn PDF document text
    • https://adtw1.com/ckfinder/userfiles/files/44871611302.pdfIn PDF document text
    • https://gtnet-engine.com/ckfinder/userfiles/files/jakejagufijav.pdfIn PDF document text
    • https://iphonerepairservice.nl/app/webroot/files/userfiles/files/daluwomog.pdfIn PDF document text
    • http://bbpcosmetics.com/admin/upFiles/2021-9/file/vavilopojonego.pdfIn PDF document text
    • https://www.sistemkabin.com/ckfinder/userfiles/files/lorulukaxo.pdfIn PDF document text
    • http://shiokuda1.com/contents/files/6539237012.pdfIn PDF document text
    • http://anhuizhkj.com/upload_fck/file/2021-9-4/20210904112946678353.pdfIn PDF document text
    • http://tatagz.com/uploadfile/files/fosutapijop.pdfIn PDF document text
    • https://www.hotel-palladium.gr/wp-content/plugins/super-forms/uploads/php/files/r3q84q9ar5b8p2vgn4dqvd1gqv/xolenonirov.pdfIn PDF document text
    • https://fotobolfestmeny.hu/mvc/userfiles/file/4098971907.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/6naE_Nh8_CY/uplcv?utm_term=how+do+you+get+free+pokecoins+in+pokemon+goPDF 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_off0000e509.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE509 18972 bytes
SHA-256: 86a135ea6eb2bdc7c55b642851a5000ff3e70a619846baf193a9bd32670ada3a
font_01_sfnt_off0001171d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1171D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012f34.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12F34 11140 bytes
SHA-256: 432ffbd16c11acaf2eca8e50356dfc307146fc0f047a91d327aa6bf9412de61a