Malicious PDF — malware analysis report

Static analysis result for SHA-256 3131c608b86a7ea8…

MALICIOUS

PDF

85.0 KB Created: 2021-09-18 03:35:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: e9a2666c5bbaf83bc6a4260ae9294a56 SHA-1: cf18c732d82a12d20e089804cf190b085a112fa7 SHA-256: 3131c608b86a7ea88c4096e143405cbfe4a0d5c2e277bca5a795621282d18f2c
156 Risk Score

Malware Insights

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

The PDF contains numerous links, many pointing to compromised websites or disposable hosting, indicative of a link farm used for phishing or malware distribution. ClamAV detected this as 'Pdf.Phishing.Trojan', and ML classification strongly supports maliciousness. The document body is heavily obfuscated and unreadable, providing no direct user-facing content, but the heuristic firings clearly indicate a malicious intent through its link structure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

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 http://sushrutproctology.org/ckfinder/userfiles/files/mikegalumixumano.pdf
    • https://www.sir.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1613685e6061d9---zerabesukakujugarixatigoj.pdf
    • https://rajnnuhiddje.se/userfiles/file/6979910274.pdf
    • http://majorpropertygroup.com/userfiles/files/18076209276.pdf
    • http://touristclub.in/userfiles/file/kileriru.pdf
    • http://sunpix.ru/img/lib/file/zojolugofidez.pdf
    • http://otoozevran.com/resimler/files/92070137901.pdf
    • http://imbirimbir.ru/files/gijexixikisetefudodudo.pdf
    • http://komputerzagrosze.pl/userfiles/file/28064030746.pdf
    • http://www.hptindia.com/wp-content/plugins/formcraft/file-upload/server/content/files/16144d91ddf12a---74556513865.pdf
    • https://www.sharpeningfactory.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613de4358f015---nifitipir.pdf
    • https://mahae.hu/files/files/kobilax.pdf
    • http://xn--h49al71atridzo.com/userData/board/file/ratopopifivazutisinowax.pdf
    • http://www.ciesol.es/ckfinder/userfiles/files/devodeve.pdf
    • https://diversifiedhumansolutions.com/wp-content/plugins/super-forms/uploads/php/files/0f87bd6ae652e30970621ec0e0fad558/87685512451.pdf
    • http://cloudinfo01.smartevolve.com/images/ckeditor/files/zategebawufonavapi.pdf
    • http://namthangbasaltstone.com/uploads/image/files/67145771320.pdf
    • http://churchliferesources.org/wp-content/plugins/formcraft/file-upload/server/content/files/16145150e5444b---rofezudupa.pdf
    • http://nenkin-t.com/upload_img/ck/files/xenog.pdf
    • http://supragyn.cz/userfiles/file/rotanokugalizakumafamizev.pdf
    • http://elmbbq.com/uploads/files/duzipubuzuromipugo.pdf
    • https://aquaticlandscape.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613fbe359fd28---9091005625.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/FevRqgeaUVY/uplcv?utm_term=doublepod+podcasts+for+android
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ea46.bin
a5763b44f9fd986f28ac58e0cb3bfbc7a0859d624efa32670f33f65d2bf9c3b8
pdf-font-stream PDF embedded font (sfnt) at offset 0xEA46 16848 bytes
font_01_sfnt_off0001160b.bin
0ec6c6dcbe1d0540c348b1f2ebc0fe6c7c0e20639a51dbe9c1b5e4ebdf73513f
pdf-font-stream PDF embedded font (sfnt) at offset 0x1160B 10856 bytes
font_02_sfnt_off00012ef9.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x12EF9 16792 bytes