Malicious PDF — malware analysis report

Static analysis result for SHA-256 8e0db39101bb5efc…

MALICIOUS

PDF

82.3 KB Created: 2021-09-07 23:13:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: a4ffeffb4d91f5e4a114d84a55031bc9 SHA-1: bff4ccc16c3b773edc9c04d67d44e8a8ae8a736d SHA-256: 8e0db39101bb5efcccb08d4340121079a375593b0482dcc68f5fc37ea4ad428e
156 Risk Score

Malware Insights

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

The sample was identified as malicious by ML classifiers and ClamAV, specifically as a phishing trojan. Static analysis revealed it functions as a link farm, containing numerous URLs pointing to other PDF files hosted on compromised websites. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates a pattern of using disposable hosting for these links, suggesting an attempt to manipulate search engine results or lure victims to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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 https://quatden.vn/webroot/img/files/67021173864.pdf In PDF document text
    • https://www.die-umzugsfabrik.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f1e3488c28---pobemeporox.pdfIn PDF document text
    • http://www.leesii.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608a525c649ae---4719330205.pdfIn PDF document text
    • https://cubic.is/userfiles/file/38155678005.pdfIn PDF document text
    • http://acetuitioncentre.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16072e36c11993---16784369581.pdfIn PDF document text
    • http://thicongdiennuocmiennam.com/uploads/files/bukurazukiruvoso.pdfIn PDF document text
    • http://artdealer.vn/upload/fckimagesfile/a315938ac5575449ca51e5ddf5951561.pdfIn PDF document text
    • http://servmed.net/userfiles/file/fofilojuviguv.pdfIn PDF document text
    • https://www.tifdip.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609b8e349a8a2---lejitatapatumasawima.pdfIn PDF document text
    • http://jamesandsons.ca/userfiles/file/64665266059.pdfIn PDF document text
    • http://abogadosaguilar.com/ckfinder/userfiles/files/93263248556.pdfIn PDF document text
    • https://wfca-czech.cz/temp/userfiles/files/bameperi.pdfIn PDF document text
    • http://parkwestresidences.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609cb729498a5---73055870235.pdfIn PDF document text
    • https://sk-developers.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612698288876b---20270313208.pdfIn PDF document text
    • http://dobermanncz.eu/files/24754814134.pdfIn PDF document text
    • https://loskutova.site/wp-content/plugins/super-forms/uploads/php/files/adaed3ed25941486f13939f7e650cf37/bolaga.pdfIn PDF document text
    • https://terminal.hr/userfiles/file/dimemixefun.pdfIn PDF document text
    • https://webgirls-studio.com/wp-content/plugins/formcraft/file-upload/server/content/files/16080c81231cfa---gufidaxonufer.pdfIn PDF document text
    • http://m2m2design.com/userfiles/dubewav.pdfIn PDF document text
    • https://mrmusicfoundation.org/wp-content/plugins/super-forms/uploads/php/files/laregil5e8lkabfrbr9u99jh8s/5521890233.pdfIn PDF document text
    • http://lesen-und-schenken.de/userfiles/files/10931408650.pdfIn PDF document text
    • http://massintech.ru/img/outer/files/28043610029.pdfIn PDF document text
    • https://agilitynd.com/wp-content/plugins/super-forms/uploads/php/files/533937eed827c7f480cb47cf5dd9e4c9/43078439530.pdfIn PDF document text
    • https://webornate.com/viking1/uploads/files/41563491054.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/6naE_Nh8_CY/uplcv?utm_term=recitation+poem+for+jr+kg+pdfPDF 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_off0000dcd5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDCD5 11016 bytes
SHA-256: 66abecf61a115deb1b6e251be05be72a2f8dd7c47f2d776bdae11bf09abbc742
font_01_sfnt_off0000f62f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF62F 17796 bytes
SHA-256: 867d64becf2691450f1b45fe47365045aa669e342329a157de78dff00b30f1b2
font_02_sfnt_off000123e1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x123E1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1