Malicious PDF — malware analysis report

Static analysis result for SHA-256 4b8597b83c53074b…

MALICIOUS

PDF

70.2 KB Created: 2021-10-03 21:14:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 9800fa3862a723b6f32b64cf18c1e376 SHA-1: fe5eab8d01f857d5c54df642a7f4aaf67a68d46e SHA-256: 4b8597b83c53074b85f1dc7047c38dccd02b04102d4eb677cfaed7c05eb6b909
96 Risk Score

Malware Insights

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

The PDF file contains numerous embedded URLs, many of which point to compromised WordPress installations or disposable hosting. The ML classifier strongly indicated maliciousness, and the heuristic firings confirm the presence of a link farm designed to redirect users. No scripts were extracted, but the primary attack pattern appears to be social engineering via a malicious document, likely delivered as a spearphishing attachment, leading to further compromise through external links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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://synerhu.ru/uplcv?utm_term=blood+disorders+that+cause+anemia PDF link annotation
    • http://yuilchem.com/userData/board/file/91050857977.pdfIn PDF document text
    • https://www.hotel-palladium.gr/wp-content/plugins/super-forms/uploads/php/files/iunaa46b0gtim5babn1auhrfr5/76786113250.pdfIn PDF document text
    • http://esistore.lu/userfiles/file/fafelerexos.pdfIn PDF document text
    • http://velomagazin.hu/UserFiles/file/8362811284.pdfIn PDF document text
    • https://hacunamatata.ru/wp-content/plugins/super-forms/uploads/php/files/3ae27893d960e1b3c12b5cefdea89b4f/mofodazokovogum.pdfIn PDF document text
    • http://giasudaihocsupham.com/Images_upload/files/28715891621.pdfIn PDF document text
    • http://salocchi.it/userfiles/files/tevuxufugoruzenasubowom.pdfIn PDF document text
    • http://chandigarhdatarecovery.com/files/file/25937573949.pdfIn PDF document text
    • https://thefertilizerproductionline.com/d/files/22365382189.pdfIn PDF document text
    • https://tuabogadoangel.com/wp-content/plugins/super-forms/uploads/php/files/d57c7f25b7d9cb4aa6c04e0db3e7acb7/lomadizerafu.pdfIn PDF document text
    • https://www.babetravelling.com/ckfinder/userfiles2/files/87289548968.pdfIn PDF document text
    • http://agilesolutions.in/uploads/xebozumag.pdfIn PDF document text
    • https://nikosdimos.gr/userfiles/file/53302738590.pdfIn PDF document text
    • http://3mfa.com/images/editor/files/lunegim.pdfIn PDF document text
    • https://aczv.fr/userfiles/file/93950298155.pdfIn PDF document text
    • http://hoilhpnqbthanh.com/upload/file/97111815593.pdfIn PDF document text
    • https://doitsolutions.co/wp-content/plugins/super-forms/uploads/php/files/93a7a34b503c6277e77ed81ea8ad0045/sesevikisikikeno.pdfIn PDF document text
    • https://aarhuskortet.dk/images/file/bisorowadisa.pdfIn PDF document text
    • http://gillsandgeckos.com/userfiles/file/79279289323.pdfIn PDF document text
    • http://guchen.ru/d/files/61348863802.pdfIn PDF document text
    • https://pragatitic.org/ckfinder/userfiles/files/5110109031.pdfIn PDF document text
    • http://mmckno2010.zkosuchdol.info/files/netajili.pdfIn PDF document text
    • http://footstepfloor.com/upfiles/files/35645474321.pdfIn PDF document text
    • http://theexplorerthai.com/userfiles/files/gebogipimufuxuwiso.pdfIn PDF document text
    • 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_off0000affe.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAFFE 10788 bytes
SHA-256: 6848bc9f9e21eeb6515177930b783a28700b1fd24a13733afd6d5469a332488c
font_01_sfnt_off0000c8a9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC8A9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e0bb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE0BB 16696 bytes
SHA-256: 3a86c4c06301ec72e73278d3754cf8eacbcd6a0b28e3b3441aaa4b6412344f05