Malicious PDF — malware analysis report

Static analysis result for SHA-256 855ea2d24a7789d8…

MALICIOUS

PDF

73.4 KB Created: 2021-05-22 23:36:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-26
MD5: 099675fea77b6e4fe56fb3cc4a788b64 SHA-1: 968cd7fa190e91da7bd303a302461371ce61291a SHA-256: 855ea2d24a7789d8e58e1c0bf7a5323adb53ba02f960a9862d57d561ca163a2a
156 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating it contains malicious content. Heuristics identified it as a link farm pointing to multiple compromised WordPress upload directories, suggesting an attempt to distribute malicious files or manipulate search engine results. The presence of numerous unknown URLs further supports this malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://wakingbeauty.com/wp-content/plugins/formcraft/file-upload/server/content/files/16084fe8514c74---28047711423.pdf In PDF document text
    • http://www.191seo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606d3daec64ad---29817382568.pdfIn PDF document text
    • https://studiogreenwich.ru/wp-content/plugins/super-forms/uploads/php/files/e6042e711e2821aed9694fcf58d9978a/vebuzagipifap.pdfIn PDF document text
    • https://narimasu-chintai.net/jcfiles/file/52047102261.pdfIn PDF document text
    • https://drahmetbostanci.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607660e0565a1---61689947173.pdfIn PDF document text
    • https://www.travelticket.com.au/wp-content/plugins/super-forms/uploads/php/files/0cc7oaeoagrlsdkkvltf4m8kac/mamurazajivufupalub.pdfIn PDF document text
    • https://gtsonline.nl/wp-content/plugins/super-forms/uploads/php/files/80e7lsqtoh7buvo7ftnkqg61k2/nezigafebesiwalomevax.pdfIn PDF document text
    • http://brodart01.com/wp-content/plugins/super-forms/uploads/php/files/rmrbep73froagf4smuo4meqqco/24127915333.pdfIn PDF document text
    • http://firewheels.pe/userfiles/file/xatisuxesogujobozujakegab.pdfIn PDF document text
    • http://cbelmira.com/wp-content/plugins/super-forms/uploads/php/files/g9rb728r89tn1ph79jbfghp1u2/kunifona.pdfIn PDF document text
    • http://amwordpress.org/wp-content/plugins/formcraft/file-upload/server/content/files/1609f8404066ee---bumuvijabuniwu.pdfIn PDF document text
    • http://makaifruits.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f7ab9d0115---52981746241.pdfIn PDF document text
    • https://agrotehholding.ru/wp-content/plugins/super-forms/uploads/php/files/ed0fce4a14b191ffdfcc2172940866ef/xuziditimakenazodo.pdfIn PDF document text
    • https://mission4recruitment.com/wp-content/plugins/formcraft/file-upload/server/content/files/160723e883107d---30847473774.pdfIn PDF document text
    • https://iwnta.com/userfiles/file/sedoma.pdfIn PDF document text
    • http://www.oknookna.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160755fda0fb46---sezuboduj.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/Om9ozkHLxGw/uplcv?utm_term=what+are+3+different+forms+of+government+in+the+worldPDF 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e21c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE21C 5652 bytes
SHA-256: 9704454b9de04dbfdc4f9f33db314845996c2e2c417d076c7a453ae6264aad9a
font_01_sfnt_off0000f549.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF549 10372 bytes
SHA-256: b43a860a18d4a8c5e916f21d7bb96e112e2c77000c72782053c49810f7fa072f