Malicious PDF — malware analysis report

Static analysis result for SHA-256 533dc44ce062a803…

MALICIOUS

PDF

81.8 KB Created: 2021-09-19 14:15:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: c973278d911625eee9a67277d08ddc96 SHA-1: de7ba5490707cf372594b452e279d3f272a44597 SHA-256: 533dc44ce062a8032d7883acf8b8c992dbfc0920dd23e4227c6cb64c79e2af81
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF document contains a large number of external links, many pointing to PDF files hosted on various domains, indicating a link farm. Several heuristics flag this behavior as suspicious, including 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM'. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or distributing further malware. No scripts were extracted, but the structure itself is indicative of a malicious lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

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
  • 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://aneri12.eu/res/file/wazixulowesapugusugeni.pdf In PDF document text
    • http://weilandvloeren.nl/fckimages/73589478899.pdfIn PDF document text
    • http://wiskind.com/filespath/files/20210914004527.pdfIn PDF document text
    • https://juhaszautovill.hu/userfiles/file/42913617083.pdfIn PDF document text
    • https://barcelona-health.com/files/galeria/files/zavoteboxe.pdfIn PDF document text
    • http://tiga.co.th/ckfinder/userfiles/files/58389601597.pdfIn PDF document text
    • http://obrienbuilders.com/userfiles/file/17983806403.pdfIn PDF document text
    • http://naphogacomposite.com/upload/files/peleze.pdfIn PDF document text
    • https://www.hdcorp.com.br/wp-content/plugins/super-forms/uploads/php/files/ubf79ppdds7nqe8lv8ncjsviui/3035292736.pdfIn PDF document text
    • http://nationshield.ae/userfiles/files/rezadodiriwonomadapep.pdfIn PDF document text
    • http://dylogistics.com/userData/board/file/10539849503.pdfIn PDF document text
    • http://polyalpan.hu/_user/file/mewafuvuvewazoxexadajor.pdfIn PDF document text
    • http://chnli.tw/CKEdit/upload/files/vixakevefulef.pdfIn PDF document text
    • http://snnet.kr/board_pds/fckeditor/2021/09/file/5276007048.pdfIn PDF document text
    • http://smartvoicesys.com/userfiles/fuvevobewujojogawosobupuz.pdfIn PDF document text
    • https://samoinstitute.mn/uploads/assets/file/17960229780.pdfIn PDF document text
    • http://ydchem.cn/filespath/files/20210902181000.pdfIn PDF document text
    • http://www.driftime.ee/wp-content/plugins/formcraft/file-upload/server/content/files/161359395146f8---vovip.pdfIn PDF document text
    • http://www.caribbeandentist.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613c1032904bb---25301538879.pdfIn PDF document text
    • https://itchanoi.vn/uploads/news_file/gasitoje.pdfIn PDF document text
    • http://simsvizag.com/admin/uploadedfiles/file///76076826307.pdfIn PDF document text
    • http://humanitool.ru/userfiles/file/58941663397.pdfIn PDF document text
    • http://www.1atlanticfunding.com/wp-content/plugins/formcraft/file-upload/server/content/files/16130846b1e665---75441091282.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/zMnd8XtcwSM/uplcv?utm_term=periodic+table+in+odia+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_off0000dd2d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD2D 10588 bytes
SHA-256: 2779694978f840bd4e52c5f6168e36a2e22baca48244c718891f8ec94f0a4f41
font_01_sfnt_off0000f52d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF52D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010d3f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D3F 17312 bytes
SHA-256: 4a3ef4dcc74fca9fc7414eb147e0df0386a3e0d7d6e9d7524c7fa9954d327b02