Malicious PDF — malware analysis report

Static analysis result for SHA-256 91b940e5e509613f…

MALICIOUS

PDF

81.4 KB Created: 2021-09-14 05:49:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 564073eb633bbb8f1028e7cdf54aecb3 SHA-1: 813a7f1f948f41c0a0e1494cb58ccecc796f6c03 SHA-256: 91b940e5e509613fd32f4dcc2a6418d1de52110601c0db85b8b00369117d60f5
156 Risk Score

Malware Insights

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

The PDF contains numerous links pointing to other PDF files hosted on various websites, many of which appear to be compromised. The 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' heuristics indicate a pattern of using link farms on potentially untrustworthy hosting. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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 http://ducthanggroup.com/webroot/img/files/sokezanamos.pdf In PDF document text
    • http://prinsart.ro/uploads/files/10480174649.pdfIn PDF document text
    • http://abacusnancy.com/userfiles/file/62389973787.pdfIn PDF document text
    • http://sea-cruise.ru/ckfinder/userfiles/files/negugirikugitab.pdfIn PDF document text
    • http://yuemeism.com/uploadfiles/files/84789432128.pdfIn PDF document text
    • http://vetranhtuong.info/luutru/files/wuwevutabamowokop.pdfIn PDF document text
    • https://completecollegestrategies.com/wp-content/plugins/super-forms/uploads/php/files/5d59eda2654186bff4bb186af8dcdcb0/pegaja.pdfIn PDF document text
    • http://cedresarquitectura.com/wp-content/plugins/formcraft/file-upload/server/content/files/16134d37e9b35d---97118410189.pdfIn PDF document text
    • http://kythuatviet.vn/uploads/userfiles/file/tilifawexoguwunapazid.pdfIn PDF document text
    • http://windcampus.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613c971ed1926---31747154091.pdfIn PDF document text
    • http://studiotecnicobonoli.com/userfiles/files/25564371243.pdfIn PDF document text
    • http://sxhk365.com/uploads/file///lupawalobotosoguxosib.pdfIn PDF document text
    • http://abwingstop.com/uploads/files/gizejovo.pdfIn PDF document text
    • http://portaldeaquidauana.com.br/ckfinder/userfiles/files/fokilu.pdfIn PDF document text
    • https://mk-promotions.com/ckfinder/userfiles/files/32711244840.pdfIn PDF document text
    • http://amadesafar.ir/basefile/amadesafarir/files/kubokorosatufujozikevodek.pdfIn PDF document text
    • http://hoangduy.vn/vn/files/misagudagulodukusunazikik.pdfIn PDF document text
    • http://pharmorgsyn.com/upload/files/detefajadoterunumezegagob.pdfIn PDF document text
    • http://wxbeimei.cn/upload/ckimg/files/202109141044154132.pdfIn PDF document text
    • http://alt-1c.ru/userfiles/file/fatobojavixozi.pdfIn PDF document text
    • http://alatasfilms.gr/ILC/img/file/75765616121.pdfIn PDF document text
    • http://normel.org/files/upload/file/55920481182.pdfIn PDF document text
    • http://www.santabriganti.org/admin/ckfinder/userfiles/files/31615641138.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/6naE_Nh8_CY/uplcv?utm_term=pixel+car+racer+car+mod+apkPDF 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_off0000da79.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA79 10500 bytes
SHA-256: 4ee278204fafdaf868c3adc1ff0b14d10bff81fd0dd17ff341fa3153d4eecf7e
font_01_sfnt_off0000f256.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF256 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010a68.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A68 17604 bytes
SHA-256: 25b3deb9f795360d2d85e57aec874ca35b39766001420a73088d41d5bc4ffdd2