Malicious PDF — malware analysis report

Static analysis result for SHA-256 4cb3c17667554b28…

MALICIOUS

PDF

83.5 KB Created: 2021-09-07 11:52:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 9e960a0591be100a29f13dcc51975d04 SHA-1: fca08e2709c8eedc32b3aac8745c69cdace5cfcd SHA-256: 4cb3c17667554b289f293656abcb553f95320d1d750626f7cf17b78cc211c975
156 Risk Score

Malware Insights

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

The file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous links pointing to compromised CMS upload storage and disposable hosting, suggesting a link farm designed to redirect users to malicious sites. The presence of external URIs and the nature of the heuristics strongly suggest this PDF is used as a lure, likely for phishing or to deliver a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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 http://sinostandards.net/upload/files/nugunomoxos.pdf In PDF document text
    • https://bokseinstituttet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/160bb3d9a735ca---vinaporekazobugoximomulu.pdfIn PDF document text
    • https://izharfoster.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ae737f45803---16370500048.pdfIn PDF document text
    • http://orosweb.hu/ckfinder/userfiles/files/vuzafanuvipoduwidijunugit.pdfIn PDF document text
    • http://darec.sk/files/files/pinidus.pdfIn PDF document text
    • https://avonsteel.com/UserFiles/file/35958578744.pdfIn PDF document text
    • https://ikansambel.com/contents//files/10221647722.pdfIn PDF document text
    • https://actorconseil.com/files/file/jelinodek.pdfIn PDF document text
    • http://www.kissdocs.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160984bfa3cebe---50042347755.pdfIn PDF document text
    • http://xedaptap.net/userfiles/file/fesizemenirewesonosaxezuw.pdfIn PDF document text
    • http://sinara.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/160f41a4f9ead8---fodif.pdfIn PDF document text
    • http://xn--80aamdqpfpr.xn--p1ai/upload_picture/16435016130.pdfIn PDF document text
    • http://pi-consulting.ch/download/66025316786.pdfIn PDF document text
    • https://www.frontierexim.com/wp-content/plugins/super-forms/uploads/php/files/c54ettebin3t9b7dmfmqn61ihp/pudezovosetudogojofugire.pdfIn PDF document text
    • https://danielstrehlau.com/userfiles/file/wumodudusevekimexib.pdfIn PDF document text
    • https://www.bountyvacation.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ae844f7fd49---matip.pdfIn PDF document text
    • http://abnicum.ru/files/file/sanusemiworoxugesi.pdfIn PDF document text
    • http://www.olympussverige.se/wp-content/plugins/super-forms/uploads/php/files/6o4anmefo8k4qp6e44fjk2eh68/kitetugibedibojase.pdfIn PDF document text
    • https://wilsonbarrera.com/inicio/wp-content/plugins/formcraft/file-upload/server/content/files/16089a1111bc60---63837857359.pdfIn PDF document text
    • http://shqinze.net/admin/upimg/file///sibenigesopodipijogu.pdfIn PDF document text
    • https://www.areatransfers.com/wp-content/plugins/formcraft/file-upload/server/content/files/16116287b1152a---zogixilifunifevepoz.pdfIn PDF document text
    • https://ekselantechnology.solutions/ckfinder/userfiles/files/vedes.pdfIn PDF document text
    • https://fjordancv.info/wp-content/plugins/super-forms/uploads/php/files/fdd0d59080ab3bf032c3e5d4ff4ca24a/mixisamaganadizokoline.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/fzgW7-mxBc0/uplcv?utm_term=2008+subaru+outback+owner%27s+manual+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_off0000dd87.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD87 18288 bytes
SHA-256: 8bd53bb04eb969aad4fac5767e109d19ed2af3053aee563b1fba3dd708b5b614
font_01_sfnt_off00010cfa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10CFA 11492 bytes
SHA-256: 95246ca2ebb79c9e9f9a6bf09e3aa1c6d68d1a0c2ec906c0ed37de55ab7a7518
font_02_sfnt_off00012826.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12826 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1