Malicious PDF — malware analysis report

Static analysis result for SHA-256 581bfb491ef71c3b…

MALICIOUS

PDF

79.1 KB Created: 2021-06-25 16:58:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: a6a9cb7a45cbeb43e20cb572f72d296b SHA-1: 9ee5e121dac154ad5cdcd2db00e1e1622723141d SHA-256: 581bfb491ef71c3b65018726ee59ef4e6d6d1cdcf04007055e57d80e3393e7b7
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which point to compromised CMS upload directories, suggesting a link farm designed to host and distribute malicious files. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware distribution. While no scripts were explicitly extracted, the PDF structure and embedded links are indicative of a malicious document, potentially leveraging JavaScript for further actions.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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://akgikorea.com/file_upload/fck_upfile/file/rerusalerinebavun.pdf
    • https://www.hagensmarketing.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a74f8529004---kewujulekolin.pdf
    • http://bungefamily.com/clients/5233/File/dutumip.pdf
    • https://medgarlci.com/wp-content/plugins/super-forms/uploads/php/files/32c9c17d6727840ee5910a929c1109d7/13443421195.pdf
    • http://naturabliskociebie.pl/userfiles/file/pawadapuvoribisanavakugev.pdf
    • http://ednak.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607b2e4d9346d---fipepexazov.pdf
    • http://obrienbuilders.com/userfiles/file/81872421343.pdf
    • http://chinahongji.com/d/files/wurifinif.pdf
    • https://fetogram.com/images/upload/files/4166961824.pdf
    • https://mn-lawfirm.com/box/userfiles/file/riwijigorife.pdf
    • http://foire-fromages-et-vins.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d1afaf53e66---55938161503.pdf
    • http://www.uvhk.com/wp-content/plugins/formcraft/file-upload/server/content/files/160862183eb784---28734282909.pdf
    • http://merrygoldholidays.com/ckfinder/userfiles/files/gudotevab.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/GLLx1DTH0VQ/uplcv?utm_term=easy+pdf+to+word+converter+free+download+full+version
    • 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_off0000d14e.bin
62d537c96635428270615d657f7b59ad23676bade4ca9f5a97a1b1185c6eef34		 pdf-font-stream PDF embedded font (sfnt) at offset 0xD14E 10964 bytes
font_01_sfnt_off0000eaeb.bin
5972750bd95b0ed22a4a1f5db9a80e52936dd28a97df9aebbd66f8fcca6a9efc		 pdf-font-stream PDF embedded font (sfnt) at offset 0xEAEB 17044 bytes
font_02_sfnt_off0001176d.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0x1176D 16792 bytes

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