Malicious PDF — malware analysis report

Static analysis result for SHA-256 51ef25f0671a4a45…

MALICIOUS

PDF

96.1 KB Created: 2021-09-09 23:59:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: daefc475da03f1fdc2b1a138413e33b4 SHA-1: 715b9d83428a4c346597ab8b54ffe39467faf05e SHA-256: 51ef25f0671a4a4510df54a2113bb3204fa783d93909c41fbc85aadb7fafafaa
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Numerous external URLs were extracted, many pointing to compromised CMS uploads or disposable hosting, suggesting a link farm or phishing lure. The PDF structure and embedded content, though heavily obfuscated, are consistent with techniques used to redirect users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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 https://garglob.ru/uplcv?utm_term=1+2+3+4+player PDF link annotation
    • http://yung-shun.com/userfiles/file/4100918874.pdfIn PDF document text
    • http://fujavietnam.com/images/Download/petizelo.pdfIn PDF document text
    • https://avis-medical.ma/wp-content/plugins/super-forms/uploads/php/files/05b66e77d8a765417f130009f98c0ebb/92543243386.pdfIn PDF document text
    • http://fobas.cz/userfiles/file/gikum.pdfIn PDF document text
    • http://jfac.kr/ckfinder/userfiles/files/wejivaxejenebinaza.pdfIn PDF document text
    • https://www.pietri-automobiles.com/wp-content/plugins/super-forms/uploads/php/files/trsvmda1g3src64qkm2fe07mo5/makirutaxebuduzuvetil.pdfIn PDF document text
    • http://sro52.ru/uploads/files/38243491231.pdfIn PDF document text
    • https://controlcert.se/wp-content/plugins/formcraft/file-upload/server/content/files/161399941a4bf0---duxatufabolu.pdfIn PDF document text
    • https://highfieldhousehotel.net/nbloom/fckuploads/file/77070655813.pdfIn PDF document text
    • http://kernenshepler.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/19058475355.pdfIn PDF document text
    • http://musicandyouapp.com/webupload/editorimg/files/govafolomuruwaw.pdfIn PDF document text
    • http://urotunisia.com/uploads/FCK_files/file/59558625798.pdfIn PDF document text
    • https://avantkart.com/wp-content/plugins/super-forms/uploads/php/files/h9umnempaktei8oj1oun0tm7de/73147586990.pdfIn PDF document text
    • http://www.pattyn360.com/upload/forum/files/vurazugenibagotu.pdfIn PDF document text
    • http://gcsiva.com/files/userfiles/file/wazuviliwujibim.pdfIn PDF document text
    • https://kanat.com/upload/ckfinder/files/7227303113.pdfIn PDF document text
    • https://it-remarketing.pl/app/webroot/media/files/fesapufuwi.pdfIn PDF document text
    • http://www.caribbeandentist.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f00b4abcaf---22581253655.pdfIn PDF document text
    • http://makaifruits.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f6972eb87e---21782556980.pdfIn PDF document text
    • http://ipai-bg.eu/img/file/80625136876.pdfIn PDF document text
    • http://tinhdaurosa.com/Images_upload/files/15297970938.pdfIn PDF document text
    • http://tainghe.vn/userfiles/file/48448836895.pdfIn 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://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_off0001145d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1145D 18448 bytes
SHA-256: db29c1ab507f773e6425b5b2535f49306853cd57a35390d904d660642c95286f
font_01_sfnt_off00014469.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14469 10104 bytes
SHA-256: b308337fa5184de0534b13bb4acc37d2ef582fdaffd810332fe71de665e758db
font_02_sfnt_off00015b2a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15B2A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1