Malicious PDF — malware analysis report

Static analysis result for SHA-256 0638c44a51cc37f1…

MALICIOUS

PDF

79.4 KB Created: 2021-09-16 19:23:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: e8170d45fb02446eef0284eadbf34433 SHA-1: 7439c2631a67cacdded92a83808a96bf55026bfc SHA-256: 0638c44a51cc37f1bff0807e5e6836228a738b0698a99c9d72289463d34cc68b
176 Risk Score

Malware Insights

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

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It functions as a link farm, with numerous embedded URLs pointing to potentially compromised or disposable hosting sites. The presence of PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics further supports this, suggesting an attempt to distribute malicious content or phish users.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 7

  • 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.
  • QR-code redirect lure medium SE_QR_LURE
    Document instructs the user to scan a QR code with a phone — consistent with QR phishing, but also common in legitimate documents
  • 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://www.contal-farmer.com/uploads/files/kajebexafuwerifek.pdf In PDF document text
    • https://cowichanmusicfestival.com/userfiles/file/48958217380.pdfIn PDF document text
    • http://czechnews.cz/userfiles/files/13363297121.pdfIn PDF document text
    • http://ettermanenterprises.com/ckfinder/userfiles/files/75180280871.pdfIn PDF document text
    • http://ck-kutnahora.cz/gais/image/file/likimebeninek.pdfIn PDF document text
    • https://98ing.com/upload/ck/files/20210903_082504.pdfIn PDF document text
    • http://urparitet.ru/admin/ckfinder/userfiles/files/20798082740.pdfIn PDF document text
    • https://hinaweb.com/upload/file/70186189388.pdfIn PDF document text
    • https://www.focus.mu/wp-content/plugins/super-forms/uploads/php/files/63517da37669a858a0ffcbe97044b90b/97009187597.pdfIn PDF document text
    • https://westhigienia.hu/editor_up/masivejaxedadivud.pdfIn PDF document text
    • http://hotelbasantresidency.com/uploads/botavubafejubenejip.pdfIn PDF document text
    • https://baruipur.org/ckfinder/userfiles/files/2016906081.pdfIn PDF document text
    • http://aedelsur.com/contenido/files/65926441477.pdfIn PDF document text
    • https://takarasushimn.com/userfiles/files/57088613282.pdfIn PDF document text
    • https://spa-salon.ru/ckfinder/userfiles/files/worapexegijevugi.pdfIn PDF document text
    • https://agsposure.org/wp-content/plugins/super-forms/uploads/php/files/887bfdb9d9f1f93b5cecc3bc05099029/wereludigazikakiwogarewa.pdfIn PDF document text
    • http://salman-is.com/userfiles/file/42827618340.pdfIn PDF document text
    • http://edwindijk.nl/home/edijk/domains/edwindijk.nl/public_html/uploads/file/fewurigerosujerag.pdfIn PDF document text
    • https://www.tai.gr/wp-content/plugins/formcraft/file-upload/server/content/files/1613888064ae79---dibovurosajune.pdfIn PDF document text
    • https://kurtoglumob.com/upload/file/56231782613.pdfIn PDF document text
    • https://redac.ch/upload/pipij.pdfIn PDF document text
    • http://ildungrice.com/fileupload/fckeditor/file/71690421211.pdfIn PDF document text
    • http://tuzoltosagmihald.hu/userfiles/file/xuzufiwojogoxoleg.pdfIn PDF document text
    • http://studiovalentini.eu/userfiles/files/xopamikujaj.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=free+skin+among+us+apkPDF 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_off0000cfd9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCFD9 10620 bytes
SHA-256: 8a2f877d46bb09feec59006e4dfdbcfd68eb79ed8e125065d91ef8e8a8e73ad1
font_01_sfnt_off0000e819.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE819 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001002b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1002B 18348 bytes
SHA-256: e7121ff0b90da084b7a5f6bf85f797a679199d1411d2c31900d1b818ec8cb76b

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