Malicious PDF — malware analysis report

Static analysis result for SHA-256 cb4550b9e44567ac…

MALICIOUS

PDF

73.6 KB Created: 2021-09-25 17:36:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 8dc32263a052f7456a70822d2ed416ed SHA-1: da532f735934f6ea6f7a0f212eec188db699a337 SHA-256: cb4550b9e44567accb43b43f7991faf316c608360bf3e2001e397dbec10d0e6a
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The ML classifier and ClamAV detection strongly indicate malicious intent. The PDF contains a link farm pointing to multiple domains, including compromised WordPress sites, suggesting an attempt to distribute further malicious content or phish users. The presence of numerous external URIs and a link farm heuristic confirms the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9885

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://wfbulgaria.com/uploads/wysiwyg/files/revun.pdf In PDF document text
    • http://cartonwrappingmachine.com/userfiles/file/dumubujofor.pdfIn PDF document text
    • http://hertzlaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/80274646627.pdfIn PDF document text
    • https://mamadona.ru/ckfinder/userfiles/files/7911969764.pdfIn PDF document text
    • http://vanprodukt.cz/UserFiles/File/lofubivodetadojo.pdfIn PDF document text
    • http://www.stratcareerservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613394c761075---9354345094.pdfIn PDF document text
    • https://gtsonline.nl/wp-content/plugins/super-forms/uploads/php/files/t37h0vhe25b204uu340vjgku60/47132106087.pdfIn PDF document text
    • http://hzqzg.com/d/files/gexaganasipug.pdfIn PDF document text
    • http://expresskaliski.info/file/diwipuvataj.pdfIn PDF document text
    • https://kochitaxirental.com/ckfinder/userfiles/files/dejeve.pdfIn PDF document text
    • https://absoluteanytime.com/media_file/files/files/65214813409.pdfIn PDF document text
    • https://tidaksusah.com/contents/files/30876765188.pdfIn PDF document text
    • https://alebusph.centralcms.cloud/galeria/files/692510770.pdfIn PDF document text
    • http://sarkar.ie/userfiles/file/40821576191.pdfIn PDF document text
    • https://www.lorenzofranzone.it/wp-content/plugins/super-forms/uploads/php/files/8383b85091511940b4f604efba5b145b/13122339907.pdfIn PDF document text
    • http://erfolgsapp.de/wp-content/plugins/formcraft/file-upload/server/content/files/16138799a9943a---99454801003.pdfIn PDF document text
    • http://paradoxine.com/upload/files/79435188358.pdfIn PDF document text
    • http://www.psoealora.es/ckfinder/userfiles/files/3674557854.pdfIn PDF document text
    • https://karapinler.com/calisma2/files/uploads/10989784314.pdfIn PDF document text
    • http://446888.top/userfiles/file/59722476670.pdfIn PDF document text
    • https://gmt-tw.com/app/webroot/userfiles/files/30806860200.pdfIn PDF document text
    • http://josephfellerlaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/50402329060.pdfIn PDF document text
    • http://www.serenissimaservizi.com/files/64503858752.pdfIn PDF document text
    • https://jxlmedu.com/file/files/20210920_182249.pdfIn PDF document text
    • http://3gr-group-com.gbintl.com/ci/userfiles/files/69746910192.pdfIn PDF document text
    • http://seoulsquare.com/userfiles/file/28679455222.pdfIn PDF document text
    • http://mgtofubbq.com/uploads/files/52415154528.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=play+minecraft+dungeons+for+freePDF 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_off0000b6b0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB6B0 19020 bytes
SHA-256: 4d92d3fbf0fc3bc615d7c7a3c9d5d59a1b651f216db0c395cecea377e71d7779
font_01_sfnt_off0000e76f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE76F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000ff86.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF86 11032 bytes
SHA-256: 5d0948d7d85e5da40b94cff14b3f03b91bb69c3b2c107d7c0e9a404024eb2219