Malicious PDF — malware analysis report

Static analysis result for SHA-256 635f1bb39d861cb6…

MALICIOUS

PDF

91.1 KB Created: 2021-07-25 20:17:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-22
MD5: 4a7f0087fde13944ed6da1c11f7228fc SHA-1: 099e29e694f6c564cc30a8f3458e2c6d063662c6 SHA-256: 635f1bb39d861cb6f34ab190cef0900f8aea4a7ce707727fc58a12f12a35ea51
156 Risk Score

Malware Insights

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

The PDF contains a large number of links, many of which point to compromised CMS upload directories and disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely to phish users or redirect them to malicious content. The primary attack pattern observed is the use of a link farm to distribute malicious URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://rescue.bg/wp-content/plugins/formcraft/file-upload/server/content/files/160a16da8a5e54---31138898657.pdf In PDF document text
    • http://safarang.com/basefile/files/fewamokerupukiw.pdfIn PDF document text
    • http://etasystem.net/userfiles/files/85091538966.pdfIn PDF document text
    • http://www.asejnrtigers.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1608bd58820d78---kijiruzekipisanajukaralo.pdfIn PDF document text
    • http://veronicanealhome.com/wp-content/plugins/formcraft/file-upload/server/content/files/2/160a8157ab5647---rugapazezejax.pdfIn PDF document text
    • https://ottenburger.com/userfiles/file/94853369067.pdfIn PDF document text
    • http://weberstellen.ch/userfiles/file/senafokevizewowopawekagut.pdfIn PDF document text
    • http://come2menorca.com/images/file/gopoxapanufezunekox.pdfIn PDF document text
    • https://gionggiacam.com/ckfinder/userfiles/files/96769168329.pdfIn PDF document text
    • https://k-barrierfree.com/FileData/ckfinder/files/20210710_FEA77264282A000F.pdfIn PDF document text
    • http://ipsgroupjjn.org/userfiles/file/xiputalinigazeme.pdfIn PDF document text
    • https://insights3.com/wp-content/plugins/super-forms/uploads/php/files/2b38ac142184ccb2bc5f0f9abc7d5f1d/jibisizasowevikotut.pdfIn PDF document text
    • http://passaicvalleyclassof1957.com/clients/44362/File/24810822181.pdfIn PDF document text
    • http://adabaskimerkezi.com/upload/file/barezasamukitubosejiro.pdfIn PDF document text
    • http://sumosushingrill.com/uploads/files/90131588552.pdfIn PDF document text
    • https://transcendenceit.com/wp-content/plugins/super-forms/uploads/php/files/825c35941f90f076616b800e4a237426/45957344693.pdfIn PDF document text
    • https://ohligschlaeger-berger.de/wp-content/plugins/formcraft/file-upload/server/content/files/160a59e5d36ccc---neduradinufuzekonet.pdfIn PDF document text
    • http://kingcraftviet.com/uploads/ckfinder/files/34265772276.pdfIn PDF document text
    • https://abril.pe/wp-content/plugins/super-forms/uploads/php/files/2eoii3ghgop3r31pdcknbrs9f6/waxiripupodideja.pdfIn PDF document text
    • http://myphamnanyno.com/luutru/files/7929849490.pdfIn PDF document text
    • http://ozari-ua.com/files/file/33404700014.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/FevRqgeaUVY/uplcv?utm_term=historia+de+la+fealdad+capitulo+7+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_off0000fcf6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFCF6 10648 bytes
SHA-256: 40f74a4945612b7f6eacd8abb59cbc982d5bef7951d8ecf60d338ba765803d57
font_01_sfnt_off0001157b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1157B 18676 bytes
SHA-256: 80af4628e215c104ac0d153573acfd9b1f6fc1c31c1eed80ed9fec8915de4080
font_02_sfnt_off000144c8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x144C8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1