Malicious PDF — malware analysis report

Static analysis result for SHA-256 648ce9efa5d8b93d…

MALICIOUS

PDF

71.9 KB Created: 2021-09-03 16:52:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: def7b90a3a30bd5a37ab31108dc60c66 SHA-1: 81cc2a1155fc75bae821bc49d0905b6dba9d8fd6 SHA-256: 648ce9efa5d8b93d0c74e98bb1d05db4d6d9b4d78a68744177b30caf85e1e8a0
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous external URLs, many of which are hosted on compromised CMS uploads or disposable domains, suggesting a link farm designed to redirect users. The presence of PDF-specific heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' reinforces the conclusion that this PDF acts as a lure to external, potentially malicious, websites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://smidgel.ru/uplcv?utm_term=free+victorian+modern+cursive+worksheets+pdf
    • https://zemiigori.com/uploads/file/95430593100.pdf
    • http://milcontabil.com.br/wp-content/plugins/super-forms/uploads/php/files/j13agdit0mapv27r123jls4ro1/boxesorarosapotorugat.pdf
    • https://jerseyshorepirates.com/userfiles/files/96908102697.pdf
    • http://ranjitabiswas.com/userfiles/files/jeveme.pdf
    • http://beloit1962.com/clients/8/83/8368a4f838dea3176655029ae9e337da/File/tubanudadavodixipuzil.pdf
    • https://www.kiteschule-kiel.de/wp-content/plugins/formcraft/file-upload/server/content/files/160db9a7932387---vadov.pdf
    • http://sportsgarten.com/editorData/file/77965770284.pdf
    • http://hamyarsanatco.com/ckfinder/userfiles/files/ruwitowexox.pdf
    • http://bouwbedrijfansing.nl/userfiles/file/51247881376.pdf
    • http://www.fliesen-brill.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607ead6a31649---mupax.pdf
    • https://admonks.ru/wp-content/plugins/super-forms/uploads/php/files/79af3678d2e176405a983fd4d287e1a7/94073356312.pdf
    • https://www.colegiodesafio.net/home/wp-content/plugins/formcraft/file-upload/server/content/files/160b2a62fc6696---waviwivam.pdf
    • http://le-lemniscus-incandescent.fr/ckeditor/upload/files/65617497674.pdf
    • http://viaterrestre.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1608ec4be8f21b---52079914543.pdf
    • http://yuseigachi.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1608f592c4e6d4---mavowatekara.pdf
    • http://ahchala.com/img/file/fodaxapodurubikefazes.pdf
    • https://kayakbranson.com/wp-content/plugins/formcraft/file-upload/server/content/files/16129484fc75b5---bokuxudojejakiladili.pdf
    • https://afd.me.uk/wp-content/plugins/super-forms/uploads/php/files/suq184gfaq5eevrnn0a6lcpbuk/64549138266.pdf
    • https://www.sevgiliyevideo.net/wp-content/plugins/formcraft/file-upload/server/content/files/1606cf49889301---rafogusivi.pdf
    • http://www.jindatunnel.com/up_files/file/44035254301.pdf
    • https://eol.org.pe/ckfinder/userfiles/files/99707629609.pdf
    • https://stefandes.com/wp-content/plugins/formcraft/file-upload/server/content/files/1610058a871ac0---zutomugogefukero.pdf
    • https://amkboiler.com/wp-content/plugins/super-forms/uploads/php/files/lvgsl4pj6h1v6invtuqo8hqkii/56983510482.pdf
    • https://grandplaza.bg/uploads/assets/file/6003994532.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b72f.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xB72F 16792 bytes
font_01_sfnt_off0000cf41.bin
3e274a6b7535c060a6953c0b86017a894a1e844e0c3da42725d9546bd130c5c4
pdf-font-stream PDF embedded font (sfnt) at offset 0xCF41 15916 bytes
font_02_sfnt_off0000f7be.bin
5a1b3f22c8dbf6bd1dedd6ff2d79b0c1b8fdade7f1a965c651be536e3a26fdbd
pdf-font-stream PDF embedded font (sfnt) at offset 0xF7BE 11160 bytes