Malicious PDF — malware analysis report

Static analysis result for SHA-256 f33b909fa6c81a81…

MALICIOUS

PDF

67.7 KB Created: 2021-06-15 15:35:34 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-24
MD5: 6ce1bf8ef0727a60f6841216b074f9ff SHA-1: 2f035c6555acf19a3ab74a6b97595579fb5b9c7e SHA-256: f33b909fa6c81a8167663ef1e2801b809f204eb9d44113eaf368f6bf41303176
96 Risk Score

Malware Insights

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

This PDF file functions as a link farm, containing numerous embedded URLs that point to compromised websites. The ML classifier strongly indicated maliciousness, and the heuristics suggest the document is designed to redirect users to potentially harmful content, likely for phishing or malware distribution. No scripts were extracted, but the extensive use of external links is a strong indicator of malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • 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://coretry.ru/uplcv?utm_term=grandma+climbs+a+tree+poem+in+english PDF link annotation
    • http://www.stallionreadymix.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160940985ce1f0---pamagora.pdfIn PDF document text
    • http://www.fullertherapy.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607227169e034---niwiloseradexowuka.pdfIn PDF document text
    • http://fitviewer.biz/files/file/79488360251.pdfIn PDF document text
    • http://omonetach.pl/foto/ilustracje/file/natineletafeze.pdfIn PDF document text
    • http://www.fsnn.se/wp-content/plugins/formcraft/file-upload/server/content/files/1607dd1ac2f22b---73531727324.pdfIn PDF document text
    • https://www.capitalroofingct.com/wp-content/plugins/formcraft/file-upload/server/content/files/16084f025e5b37---wewaganokujeke.pdfIn PDF document text
    • http://zadonskiy.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160a786e1195bf---dulilenosojumafiliko.pdfIn PDF document text
    • http://i-dron.cz/data/file/29000391714.pdfIn PDF document text
    • http://kindervakantieweekdeurne.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1607a943a32796---7652070526.pdfIn PDF document text
    • http://vtdsbinhthuan.vn/public/uploads/userfiles/file/jojezanemukibib.pdfIn PDF document text
    • http://amako-ra.com/wp-content/plugins/super-forms/uploads/php/files/ccdcc42953915a170124f9af1311e373/safanobikopabuwa.pdfIn PDF document text
    • https://topinsolventa.ro/userfiles/file/guremovojin.pdfIn PDF document text
    • https://www.truesdalepainting.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b480b32a5a4---vifomemugukemasunigozifi.pdfIn PDF document text
    • https://vildmarksjagt.dk/userfiles/file/4090572889.pdfIn PDF document text
    • http://statsale.com/data/upload/ck/files/sozulovov.pdfIn PDF document text
    • https://cosalesrep.com/wp-content/plugins/super-forms/uploads/php/files/41360a220c3022a205ddb511620e4752/16494456191.pdfIn PDF document text
    • http://profisystem.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160a7e08a17f69---88539552909.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000cb67.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCB67 5656 bytes
SHA-256: ba9f1618637d5bd14a76a4a09024269ef9237d0f31c2b53c19da474781c11b82
font_01_sfnt_off0000de73.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDE73 10440 bytes
SHA-256: 333aa57f531e6f6a79bbc7c50b36fe50547d8919055638816e00b3996c6e7705