Malicious PDF — malware analysis report

Static analysis result for SHA-256 6725f3cc6e4e0c19…

MALICIOUS

PDF

83.9 KB Created: 2021-06-30 00:19:35 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-25
MD5: 0eee39302701d43019b2061c74840a6e SHA-1: e210accf76d9e724918bb0f848d33dcd57d91508 SHA-256: 6725f3cc6e4e0c19eb067b647186adb231966f1d97387f5ea98507032d8aced9
156 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous URLs pointing to compromised WordPress upload storage and other potentially malicious sites. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for human readability but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

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://3duct.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607d808d3454b---13147445167.pdf In PDF document text
    • http://johncarroll1967.com/clients/1/18/1896e795ecc2602204d707ec4e69586f/File/38113794399.pdfIn PDF document text
    • https://groupburuemas2.com/contents//files/29830193041.pdfIn PDF document text
    • http://ontheedgeofnow.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b3657e4dc20---3203624200.pdfIn PDF document text
    • https://stalbeckers.nl/userfiles/image/file/xozazugeni.pdfIn PDF document text
    • https://empylean.com/wp-content/plugins/super-forms/uploads/php/files/rnt7lp56jbhar6soks5gftj7e6/85839504218.pdfIn PDF document text
    • https://realimpacto.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160af6e4d86d5e---repisixadakomufilunije.pdfIn PDF document text
    • https://bnbcostaverde.it/userfiles/file/fefogesuwoje.pdfIn PDF document text
    • https://controlcert.se/wp-content/plugins/formcraft/file-upload/server/content/files/160c8b9e1e9448---nujesamexosovazu.pdfIn PDF document text
    • http://hydrem.ru/images/file/41275019052.pdfIn PDF document text
    • http://makesomenoise.hu/upload/file/92848606129.pdfIn PDF document text
    • https://acavacecio.it/userfiles/files/78696437579.pdfIn PDF document text
    • https://mosoptagro.ru/wp-content/plugins/super-forms/uploads/php/files/0afc53bdbf56267be92f578f58bbe9b8/3010611505.pdfIn PDF document text
    • http://classtool.info/upload/files/52790777066.pdfIn PDF document text
    • https://xaydungdonggia.com/app/webroot/files/images/pages/files/1599183975.pdfIn PDF document text
    • http://grimastone.ru/files/danizatif.pdfIn PDF document text
    • http://bioident.pl/photos_fck/file/3163225175.pdfIn PDF document text
    • http://www.myhhsi.com/wp-content/plugins/super-forms/uploads/php/files/11771571d4afa18e3a48fbf3cf1dbd72/limajineponimovu.pdfIn PDF document text
    • https://amirep.com/wp-content/plugins/super-forms/uploads/php/files/f8b3dd27461fef98e4d56d68f139f928/favijusikunap.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/ngfLrbzwjls/uplcv?utm_term=recapitalization+private+equityPDF 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_off0000e3bb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE3BB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fbd2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFBD2 10732 bytes
SHA-256: e6e546aeba67ca0d466a2193696e103b5d9012976a04b17938c2a087082064ea
font_02_sfnt_off000114a5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x114A5 17428 bytes
SHA-256: 9a029c54288e362b426471032dab60b20bcf7ac35e33cf0ea530532e8a4471ed