Malicious PDF — malware analysis report

Static analysis result for SHA-256 c2c20e23718a4fda…

MALICIOUS

PDF

93.3 KB Created: 2021-07-19 15:01:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: d5c73b32b2f03fe692fc05703e5d29dd SHA-1: d77ed87fd7bc2497472d744025363794aba6d163 SHA-256: c2c20e23718a4fdafa3470877cacd220449c8e79b4c473575816ee659ed8dcae
96 Risk Score

Malware Insights

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

The sample is identified as malicious by an ML classifier and exhibits characteristics of a link farm. Multiple heuristics indicate the presence of numerous external links, some pointing to compromised CMS upload directories. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9935

Heuristics 5

  • 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://eminencesolutions.in/resources/userfiles/file/75755603317.pdf In PDF document text
    • https://www.yoursurveysurveyors.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160c3ff038f172---68075150638.pdfIn PDF document text
    • http://t-p-fortune.com/userfiles/file/10510226992.pdfIn PDF document text
    • https://almuhja.com/ckfinder/userfiles/files/6435542755.pdfIn PDF document text
    • http://neurooperations.com/ckfinder/userfiles/files/midofenurem.pdfIn PDF document text
    • http://zadonskiy.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1607fd3703f09c---4493524550.pdfIn PDF document text
    • http://adaviestransportltd.com/userfiles/file/18479511407.pdfIn PDF document text
    • https://evocative.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160c19a24e07d0---25351925830.pdfIn PDF document text
    • https://www.siemers-deutschmann.de/wp-content/plugins/super-forms/uploads/php/files/vs09po1g1u37ljgn9tfo195di7/6150434637.pdfIn PDF document text
    • http://travelport.pl/userfiles//file/xukite.pdfIn PDF document text
    • http://montazerangroup.com/uploader/file/meputajumitoworimebo.pdfIn PDF document text
    • http://jakpaisanestate.com/images/upload/files/24694003717.pdfIn PDF document text
    • https://wavesmaroochydore.com/wp-content/plugins/super-forms/uploads/php/files/8c9fp1b0vvqq0ev401inpqq595/reruxogisizipiwefekasifu.pdfIn PDF document text
    • https://incoyun.com/calisma2/files/uploads/gavijoneme.pdfIn PDF document text
    • https://askisan.com/upload/ckfinder/files/20882947224.pdfIn PDF document text
    • http://xn--90ad5ackt1d.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/99266dfd3962a02aedbd85b12ae431c2/40820445563.pdfIn PDF document text
    • http://doudou.tw/userfiles/files/xudolurizudil.pdfIn PDF document text
    • http://stylist.in.ua/wp-content/plugins/formcraft/file-upload/server/content/files/160be6b0f48d89---83059989476.pdfIn PDF document text
    • https://adm.allianceflooring.net/wp-content/plugins/super-forms/uploads/php/files/c4026f115a2518e852b4846fa77f11b5/tuvax.pdfIn PDF document text
    • https://mavismanagement.com/wp-content/plugins/formcraft/file-upload/server/content/files/160abf28d01d88---wixesutufazofidiva.pdfIn PDF document text
    • https://manuscripthandler.com/userfiles/file/99829655891.pdfIn PDF document text
    • http://allasclub.com/campannas/file/kogerapilepirafoxed.pdfIn PDF document text
    • http://sarlampa.ru/upload_picture/5202322079.pdfIn PDF document text
    • https://pingthye.com/userfiles/files/79787148657.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/3CAf4wW3hvY/uplcv?utm_term=naruto+all+seasons+and+movies+in+orderPDF 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_off000103c3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x103C3 20332 bytes
SHA-256: dbce23186abf0e8f7554ee9a2765f82cc0707315682c544f4bd90b221994ebf7
font_01_sfnt_off00013764.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13764 10552 bytes
SHA-256: ec07af5239fb093b2d1680d6030b7c8446ac970137654a07d125c39ffb78ebcf
font_02_sfnt_off00014f77.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14F77 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1