Malicious PDF — malware analysis report

Static analysis result for SHA-256 c5b90b60b30c7258…

MALICIOUS

PDF

80.4 KB Created: 2021-09-02 08:43:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: c9a8ae26d6c758fac3318ffe9355bd48 SHA-1: 2f71ce33719b1dd272f0b9aee3ed8a3765b2a1e9 SHA-256: c5b90b60b30c72587301cc2f07725b659793947256531f3e1c532cbe359ac26b
156 Risk Score

Malware Insights

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

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The heuristics reveal it functions as a link farm, directing users to numerous external URLs, many hosted on compromised CMS platforms. 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 0.9977

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 http://shuimotongyuan.com/userfiles/file/19198983772.pdf In PDF document text
    • http://daiichilogistics.com/uploads/news_file/1605599212.pdfIn PDF document text
    • https://alianzatours.com/imagenes/file/50522131355.pdfIn PDF document text
    • https://ercrs.org/wp-content/plugins/super-forms/uploads/php/files/j5nhvpf0nk9b9b7s3vrb8fkvpv/83891258928.pdfIn PDF document text
    • https://mvmdigital.gr/files/files/16842145601.pdfIn PDF document text
    • https://yourtuscanyguide.com/wp-content/plugins/super-forms/uploads/php/files/328bpns9563m6cg2k2o93rn906/7012576928.pdfIn PDF document text
    • https://apinero.com/wp-content/plugins/formcraft/file-upload/server/content/files/160787e499b917---73163587361.pdfIn PDF document text
    • https://sv-fin.ru/wp-content/plugins/super-forms/uploads/php/files/832661e2a91f9aeb09ec824016950686/30394671795.pdfIn PDF document text
    • http://jongauger.com/ckfinder/userfiles/files/4873747203.pdfIn PDF document text
    • https://xn--64-mlcufjjaii0l.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/6a57c221cafae8aa0dee5d4b4d7768f5/99172062372.pdfIn PDF document text
    • http://elitaliaweb.it/upload/file/76320882610.pdfIn PDF document text
    • http://wallawallahighschool1968.org/clients/75819/File/46543068225.pdfIn PDF document text
    • https://xanbiente.de/userfiles/file/1222679769.pdfIn PDF document text
    • https://torbay.ru/images/uploads/file/xipunufivanexiv.pdfIn PDF document text
    • https://backcountryplayground.com/wp-content/plugins/super-forms/uploads/php/files/432a5121e19c5fa15ea8406d32888ca6/44877021167.pdfIn PDF document text
    • http://ok-poland.com/userfiles/file/japajodukasegivajum.pdfIn PDF document text
    • http://prime42.ru/userfiles/files/benoludeli.pdfIn PDF document text
    • http://immobiliareborghi.com/userfiles/files/rigibivofo.pdfIn PDF document text
    • https://gz-topstar.com/wp-content/plugins/super-forms/uploads/php/files/6b32ed6eae9c1f01748d420b1755e5b7/17111192425.pdfIn PDF document text
    • http://bighost.vn/uploads/userfiles/file/29350030440.pdfIn PDF document text
    • http://tantex.org/tantex/tantexuserfiles/file/81845897304.pdfIn PDF document text
    • https://duext.com/wp-content/plugins/super-forms/uploads/php/files/afb4763b91f8906f5b6064a1ddffe66f/90786455284.pdfIn PDF document text
    • http://dahchen.tw/userfiles/files/gosipobisefadivivo.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/fzgW7-mxBc0/uplcv?utm_term=multithreading+interview+questions+for+experienced+in+javaPDF 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_off0000d2ae.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD2AE 17632 bytes
SHA-256: 002b34d1ba3328b1dc9341fddc738066d80a18f400327fbbe3fa19b344a6527c
font_01_sfnt_off000100b0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x100B0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000118c7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x118C7 11524 bytes
SHA-256: f483dd665d1e70b02fe2f4f3aae75789c7bc514e0700861cf909dd49ae10c390