Malicious PDF — malware analysis report

Static analysis result for SHA-256 8121231ce3296b96…

MALICIOUS

PDF

80.3 KB Created: 2021-09-10 02:34:30 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 952891c5ed6687e31950c572312fce8a SHA-1: b4e008af67b9b2cba392a4f453c84545c8407879 SHA-256: 8121231ce3296b9662b6056c72bb94dc6851998c5b19449c172f706b6ea0cebf
146 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 an ML classifier, with heuristics indicating a malformed exploit stream. The presence of numerous embedded URLs, many pointing to unknown or potentially malicious domains, suggests an attempt to redirect the user to malicious content or phishing sites. The PDF's structure and the nature of the heuristics point towards an exploit or a lure document, likely delivered via spearphishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9949

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
  • 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 https://maftplayer.net/calisma2/files/uploads/79729839236.pdf In PDF document text
    • http://www.playerclub.ro/wp-content/plugins/formcraft/file-upload/server/content/files/161341687eb6d7---kiposiwuke.pdfIn PDF document text
    • https://ofcourselc.com/admin/uploadsfile/10094758700.pdfIn PDF document text
    • https://granitnet.hu/editor_up/jevezajixipiniw.pdfIn PDF document text
    • http://shop-cartuning.pl/userfiles/file/gonakomir.pdfIn PDF document text
    • https://xn--90aoja6ahg5ds.xn--p1ai/uploads/files/wokomosegatibirodafam.pdfIn PDF document text
    • http://benthanhsgfarm.net/images/uploads/files/masuk.pdfIn PDF document text
    • https://indiantiffin4me.com/nbloom/fckuploads/file/rakatidelegul.pdfIn PDF document text
    • https://noithathoaphat11.com/upload/files/xakakufofamipulegu.pdfIn PDF document text
    • https://eownauto.com/uploadpic/files/sezirosonakozifa.pdfIn PDF document text
    • http://nokianhakkablue.ru/ckfinder/userfiles/files/rodusekinerafefetokirefuz.pdfIn PDF document text
    • http://athaj2.specialty-match.com/upload/files/muvobedemuwunikiwe.pdfIn PDF document text
    • http://ntep2008.com/UserFiles/File/6629410889.pdfIn PDF document text
    • http://travelspace.pl/userfiles/file/goxalibexizejesibebor.pdfIn PDF document text
    • http://revucue.com/ckfinder/userfiles/files/85144615878.pdfIn PDF document text
    • http://elsekmont.eu/userfiles/file/xejurap.pdfIn PDF document text
    • https://5of7edwardstreet.com/assets/media/files/marorosimiwebikuj.pdfIn PDF document text
    • http://dancephoto.ru/userfiles/files/wovajafegutobaka.pdfIn PDF document text
    • https://www.hdontheroadnapoli.it/wp-content/plugins/formcraft/file-upload/server/content/files/161390750ba726---13670082829.pdfIn PDF document text
    • http://tlumacz-lipno.pl/pdrzewiecki/files/xolitawozugegeroposepoxel.pdfIn PDF document text
    • http://franklcalabreseattorney.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/61916566322.pdfIn PDF document text
    • https://alwillislifecenter.org/ckfinder/userfiles/files/51800364164.pdfIn PDF document text
    • http://connect-event.fr/ckfinder/userfiles/files/22477141094.pdfIn PDF document text
    • https://safewatersolutions.in/ckfinder/userfiles/files/sinok.pdfIn PDF document text
    • http://cadelupo.it/userfiles/files/70808105811.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/6naE_Nh8_CY/uplcv?utm_term=selina+biology+class+8+textbook+pdfPDF 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_off0000d379.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD379 11424 bytes
SHA-256: df442847efd8d1f7bb1da4d4de7fb275dd93a5d68f9dedaab89a0f7481339888
font_01_sfnt_off0000ee30.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE30 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010642.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10642 17588 bytes
SHA-256: b817033d81cb4f93f1a838e5c87dcdcefe99259247d3cfc9e11f62cd74ddd946