Malicious PDF — malware analysis report

Static analysis result for SHA-256 aa7e28f7cd523423…

MALICIOUS

PDF

72.3 KB Created: 2021-09-17 17:13:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 13a2205435c1ecf5e81a4ae7cd146a24 SHA-1: d047c663c975e298d499b1cb78e597e34ec0ce6c SHA-256: aa7e28f7cd52342343330a49217eda35e87a4c0075e9bbc90891512498532fdc
156 Risk Score

Malware Insights

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

The PDF contains numerous links to other PDF files hosted on various domains, many of which appear to be compromised or disposable. The ML classifier and ClamAV detection strongly indicate malicious intent, likely to lure users into downloading further malicious content or engaging in phishing activities. The document body is heavily obfuscated and does not provide direct textual clues, but the overall structure and URL analysis point to a link farm attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

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://ngaa.org.au/application/third_party/ckfinder/userfiles/files/88607963812.pdf In PDF document text
    • http://quangcaosms.org/media/ftp/file/kupunabupedekalal.pdfIn PDF document text
    • http://rsti.biz/files/fck/file/2750718538.pdfIn PDF document text
    • http://www.urbanwaterways.info/files/lorawu.pdfIn PDF document text
    • https://kalyna.ua/sites/default/files/userfiles/file/vagekofojolufufokizosu.pdfIn PDF document text
    • https://egyptsuntours.com/userfiles/files/5286942490.pdfIn PDF document text
    • http://leaguengn.com/userfiles/file///96338216170.pdfIn PDF document text
    • https://12waktu.com/contents/files/9950887105.pdfIn PDF document text
    • https://swimproject.eu/wp-content/plugins/super-forms/uploads/php/files/1cc2ca094afb133764080f98223ae38a/jezonuxanoxukom.pdfIn PDF document text
    • https://trichynext.com/wp-content/plugins/super-forms/uploads/php/files/013808136dbde9609bf81b4bfca51a66/88828002144.pdfIn PDF document text
    • http://shriramashramps.org/userfiles/file/zoxameroxupefara.pdfIn PDF document text
    • http://pacemakerpressintl.com/uploads/assets/file/sisewufirujumariwem.pdfIn PDF document text
    • http://www.sintsprev-ms.org.br/ckfinder/userfiles/files/2184129476.pdfIn PDF document text
    • http://tatishev.ru/admin/ckfinder/userfiles/files/79150100129.pdfIn PDF document text
    • http://www.victorian-manor.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/16130276a51608---majupok.pdfIn PDF document text
    • http://eugensa.lt/app/webroot/uploads/userfiles/files/vusitokodulekuledixida.pdfIn PDF document text
    • http://club-integra.ru/userfiles/file/23577797063.pdfIn PDF document text
    • http://na3.it/misc/file/sokejisugifikojelubenubuw.pdfIn PDF document text
    • https://cometgroupinternational.com/ckeditor/ckfinder/userfiles/files/zesoruwejoderolakematep.pdfIn PDF document text
    • http://hophungvietnam.com/app/webroot/uploads/files/94849254438.pdfIn PDF document text
    • http://apple888.vn/luutru/files/vimililunavonuxek.pdfIn PDF document text
    • https://obermeyer-modemarkt.de/upload/file/96273493562.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=apps+download+sites+for+androidPDF 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_off0000b67b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB67B 10560 bytes
SHA-256: 1c555eb706a474ed65ddeb0e0e5846feddf62b1d9994dd8b77b701b6270e5e4f
font_01_sfnt_off0000cec8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCEC8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000e6da.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE6DA 17964 bytes
SHA-256: 686baea81989f365b60906e1a1411efc79df6be26999b8638b81e9b2789ea3f2