Malicious PDF — malware analysis report

Static analysis result for SHA-256 991d3610e29aeb4c…

MALICIOUS

PDF

80.5 KB Created: 2021-09-20 08:25:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 41773c01d7eddbb99f7ebc61d038d92b SHA-1: bea4b0987992bdcaeaebbcf3f99471d4e0ba6afd SHA-256: 991d3610e29aeb4cee0b5ac5211bc683728547e8e10b47805336596f212e3985
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which point to compromised CMS uploads or disposable hosting, indicating a link farm. The ML classifier also flagged this PDF as malicious. While no scripts were extracted, the structure and URL patterns suggest the primary purpose is to redirect users, potentially to phishing sites or malware distribution points.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9953

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://virker-ikke.dk/files/kijenu.pdf In PDF document text
    • https://orkhaconstruction.com/wp-content/plugins/super-forms/uploads/php/files/2ccl5fgpmo0k191a9dhqakha29/58474617874.pdfIn PDF document text
    • https://loyd.rs/images/file/xafepubosorab.pdfIn PDF document text
    • https://gikguamerica.com/userfiles/file/27720481727.pdfIn PDF document text
    • http://bienbao.net/uploads/files/63702722804.pdfIn PDF document text
    • https://wanna-drive.nl/files/File/29344128269.pdfIn PDF document text
    • http://www.goldenlantern.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/1612f72e5710ad---xusoxolotivomifubuzik.pdfIn PDF document text
    • http://bobmeetin.com/media/galleries/files/47990052426.pdfIn PDF document text
    • https://limadelimon.com/images/file/retekubojutalamedonutoxa.pdfIn PDF document text
    • http://websurin.net/UserFiles/File/welisufo.pdfIn PDF document text
    • https://divetechmarine.com/contents/files/vapovisemozalotorefejopi.pdfIn PDF document text
    • http://chulatutoracademy.com/chulatutor/ckfinder/userfiles/files/17567474018.pdfIn PDF document text
    • https://alismobile.co.uk/wp-content/plugins/super-forms/uploads/php/files/a6400a168e734980e1c4ff74598a5c66/zuruvexuzoripisufufaz.pdfIn PDF document text
    • https://chupwo.com/editor_upload/file/83912558375.pdfIn PDF document text
    • http://lerucherdesanges.fr/userfiles/file/jeganadubifugew.pdfIn PDF document text
    • https://jordanadams.com/ckfinder/userfiles/files/lizelisi.pdfIn PDF document text
    • https://zlataraburmevuckovic.com/files/wipamazuwatagodawa.pdfIn PDF document text
    • http://brunagabriele.it/userfiles/files/3354710402.pdfIn PDF document text
    • https://giriconsultancy.com/content_files/files/pikurinugabiduwe.pdfIn PDF document text
    • https://digiconelectronics.com/media/gevizudubiserazufumag.pdfIn PDF document text
    • http://gesht.ru/admin/ckfinder/userfiles/files/nuviwoxudepogurifoladu.pdfIn PDF document text
    • http://acevina.com/webroot/img/files/35867051451.pdfIn PDF document text
    • http://bookblog.kr/data/file/files/99447879556.pdfIn PDF document text
    • http://mdtrend.hu/files/file/77355480403.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/zMnd8XtcwSM/uplcv?utm_term=how+to+screen+a+snap+without+them+knowingPDF 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_off0000d44c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD44C 18180 bytes
SHA-256: e9525b954c24b2e53e18dfa00de1678e5cbcc37f7c237e0c1ede3d35797d57be
font_01_sfnt_off000102dd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x102DD 11044 bytes
SHA-256: b58fffd24632caa7db8e7d3815145e99765a68dbd3bc2ed4e38baac83d6861da
font_02_sfnt_off00011c71.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11C71 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1