Malicious PDF — malware analysis report

Static analysis result for SHA-256 fd1da645e0f1cc5c…

MALICIOUS

PDF

73.8 KB Created: 2021-09-12 21:56:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 34dd232d42e0e838837de9c075068a61 SHA-1: e474ef65fd9622e1d9019817c1f5db6a59ba931b SHA-256: fd1da645e0f1cc5c1a2f8f4d183af5d2d798c7cdbe05a2bc2dfa52eff77a09fd
156 Risk Score

Malware Insights

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

The sample is a PDF file identified as malicious by ML classifiers and ClamAV. It functions as a link farm, containing numerous URLs pointing to other PDF files hosted on various domains, some of which appear to be compromised CMS uploads. This suggests an attempt to distribute malicious content or manipulate search engine rankings. The presence of external URIs and link farms indicates a potential for further malicious activity or phishing.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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://naoshima-habitant.com/images/blog/file/xuxowikisaturofa.pdf In PDF document text
    • https://sakesushimn.com/userfiles/files/ruwufowi.pdfIn PDF document text
    • https://www.wemservice.com/ckfinder/userfiles/files/9653627825.pdfIn PDF document text
    • http://csc0851.com/userfiles/file/20210904130911_1hg3gd.pdfIn PDF document text
    • http://zuszdounky.cz/files/rogusowojabukim.pdfIn PDF document text
    • http://4yoga.by/pics/files/gosulakawopajuxuguwilom.pdfIn PDF document text
    • https://cornerstonelaw.eu/userfiles/file/60892209784.pdfIn PDF document text
    • http://finemetal-cn.com/upload/files/11718073433.pdfIn PDF document text
    • http://lightningriskassessment.com/ci/userfiles/files/majapazeda.pdfIn PDF document text
    • https://www.nbc.com.vn/ckfinder/userfiles/files/lokavuwumulonikisajebodu.pdfIn PDF document text
    • https://tectrongim.com/uploads/files/bupamivagijotirof.pdfIn PDF document text
    • http://hrudolf.com/userfiles/69188819889.pdfIn PDF document text
    • http://tractortools.cz/ckfinder/userfiles/files/sujejip.pdfIn PDF document text
    • https://portalbime.com/UploadedFiles/New/file/webupusuzuniwaket.pdfIn PDF document text
    • http://supragyn.cz/userfiles/file/73632825673.pdfIn PDF document text
    • http://sgrappresentanze.eu/userfiles/files/tetunanitob.pdfIn PDF document text
    • https://chatham-ebenezer.ckdomain.com/uploads/userfiles/files/38676247459.pdfIn PDF document text
    • http://www.kliningstroy.ru/wp-content/plugins/formcraft/file-upload/server/content/files/161314748f3d5e---98267404312.pdfIn PDF document text
    • https://bem-sa.com/img/file/rovudipad.pdfIn PDF document text
    • https://fortlauderdale-carservice.com/wp-content/plugins/formcraft/file-upload/server/content/files/16131baea24cb6---1588551777.pdfIn PDF document text
    • https://lorenzonimmigrationlaw.com/wp-content/plugins/formcraft/file-upload/server/content/files/161379f3f0fa22---99905728238.pdfIn PDF document text
    • https://pirkitpadangas.lt/ckfinder/userfiles/files/wolapazadawirumep.pdfIn PDF document text
    • http://onnetsolution.in/userfiles/file/63725680197.pdfIn PDF document text
    • https://rux-thai.com/ckfinder/userfiles/files/58952552823.pdfIn PDF document text
    • http://homespakistan.net/magzine/uploadfiles/file/sewozolas.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=cystic+fibrosis+pedigree+analysisPDF 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_off0000c061.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC061 15412 bytes
SHA-256: 7a89d4818ff079b4586e62ae5a588d56fa50b99c69382e6e167242fec92af965
font_01_sfnt_off0000e759.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE759 11080 bytes
SHA-256: ecde1a5d5b8c76d18c6a18b128371e101e2161132a963f456a273e8763e36818
font_02_sfnt_off000100e3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x100E3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1