Malicious PDF — malware analysis report

Static analysis result for SHA-256 dc428e99356b6f6a…

MALICIOUS

PDF

75.4 KB Created: 2021-08-25 21:49:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 2dfc9ec72ded99dfc474be92835d2ba1 SHA-1: 57fc567ccb9c8c0fcf5a42dad88f675252c8019e SHA-256: dc428e99356b6f6af80bf53f21d02ed81ba70052ac1decd0d3df716bfafc0b8b
104 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains an embedded JavaScript stream and numerous external URIs, many of which point to compromised websites or disposable hosting, indicating a link farm designed to redirect users. The ML classifier strongly flagged this PDF as malicious, supporting the assessment that it is used for malicious redirection. The embedded JavaScript likely facilitates the redirection or obfuscates the malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

Heuristics 6

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://cesishotel.lv/res/wysiwyg/file/potikubuxupadibiwuputir.pdf In PDF document text
    • https://www.karavanlakesfet.com/wp-content/plugins/super-forms/uploads/php/files/203ceb1d075a55680a677b6aa96f1667/87941559406.pdfIn PDF document text
    • http://jncs.kr/page_data/file/20210713054250.pdfIn PDF document text
    • http://opuspoint.com/ckfinder/userfiles/files/95573497679.pdfIn PDF document text
    • http://pmdrecycling.com/wp-content/plugins/formcraft/file-upload/server/content/files/16088aa3b8369b---viwobasilesu.pdfIn PDF document text
    • https://t4g.nasscomfoundation.org/wp-content/plugins/super-forms/uploads/php/files/kj8tt1mi7p5v14ut9bh06rcuv1/nidemisetupip.pdfIn PDF document text
    • https://c4ir.ae/wp-content/plugins/super-forms/uploads/php/files/arft7cese70hjju3b486qpu656/sazevunowakopulubaviva.pdfIn PDF document text
    • http://gostium.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609d2e7044608---muxenagovobuba.pdfIn PDF document text
    • https://alfa-clining.ru/wp-content/plugins/super-forms/uploads/php/files/5db4010d280d21071930ea12c53c54b7/marixamorowaxakemovubi.pdfIn PDF document text
    • https://arhstroi.by/uploads/files/56994009824.pdfIn PDF document text
    • http://cappellastudio.it/userfiles/files/86092531414.pdfIn PDF document text
    • http://anvlaw.com/userfiles/file/zofukujupikomesaz.pdfIn PDF document text
    • http://soundreaming.org/wp-content/plugins/super-forms/uploads/php/files/951da475f603613c5f547f4f352a5563/totoxejakinizirupop.pdfIn PDF document text
    • https://www.golddustdental.com/wp-content/plugins/formcraft/file-upload/server/content/files/1611b6c9272851---43115245454.pdfIn PDF document text
    • http://speed-r.com/js/upload/files/jefat.pdfIn PDF document text
    • http://ecoevopublisher.com/files/upfiles/file/votezazu.pdfIn PDF document text
    • http://theofficefurniturestore.com/ckfinder/userfiles/files/xagogavonagaduvemavudem.pdfIn PDF document text
    • http://fotografieindex.nl/images/uploads/xofapurinujoturiputed.pdfIn PDF document text
    • http://whippets-au.com/clients/7/7f/7f5032e15db821a993a8146895416847/File/bojuruje.pdfIn PDF document text
    • https://www.basur-tedavisi.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607e1de483cce---98416817737.pdfIn PDF document text
    • http://kystop.com/wp-content/plugins/super-forms/uploads/php/files/1ac1f4133ad1912bae68624e37e4430b/petirape.pdfIn PDF document text
    • http://allasclub.com/campannas/file/sulekoveboxiliw.pdfIn PDF document text
    • http://www.eflox.net/wp-content/plugins/formcraft/file-upload/server/content/files/160cf55378e8ae---40556650489.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=further+selections+from+the+prison+notebooksPDF 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_off0000c423.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC423 10892 bytes
SHA-256: f255970919f9aea165b55ee6734bcb8a666588b76240ff47f37bb8a9d70c287b
font_01_sfnt_off0000dce2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDCE2 16292 bytes
SHA-256: 985044058a6827024f2543ce65d0e25c3cd523b3961f50cf7dc0bbb9d502d9d7
font_02_sfnt_off0001074c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1074C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1