Malicious PDF — malware analysis report

Static analysis result for SHA-256 f81fc33e3b23a6cf…

MALICIOUS

PDF

149.5 KB Created: 2021-06-25 23:02:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: d4607c1cd7ea0b83af1ce98bf50aa614 SHA-1: f43bcd013bb183f9504d6563bb783bb22bce8814 SHA-256: f81fc33e3b23a6cf8e28253efd5b02cab754c3d117fc74e05292bbb7b8c8f361
156 Risk Score

Malware Insights

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

The PDF contains numerous links, many of which point to websites hosted on compromised CMS platforms, indicating a phishing or malicious redirection attempt. The ML classifier and ClamAV detection strongly suggest malicious intent. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, lacking clear user-facing content, further supporting the interpretation of it being a malicious artifact rather than a legitimate document.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9739

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://escqatar.com/uploads/userfiles/file/file/25905725711.pdf
    • http://writtenmail.com/upload_images/file/92122432367.pdf
    • http://hani-bee.com/userfiles/files/titoravuw.pdf
    • http://www.qookspot.kitchen/wp-content/plugins/formcraft/file-upload/server/content/files/160ac3c5e41c5e---jepimilu.pdf
    • http://irmascaritasdejesus.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/160a7c3f85a821---lirewivegonoketab.pdf
    • http://veivel.com/userfiles/file/5274792107.pdf
    • https://socialchangefactory.org/wp-content/plugins/super-forms/uploads/php/files/aaafaa7e82327f7fd7e273b7e912c514/8991729609.pdf
    • https://barcelonacentremedic.cat/files/galeria/files/diluvunovimukewolirodoka.pdf
    • https://www.elektrobetrieb-scholz.de/wp-content/plugins/formcraft/file-upload/server/content/files/1606c93efc033c---xetevagixedukinemidu.pdf
    • http://www.theagentpipeline.com/wp-content/plugins/formcraft/file-upload/server/content/files/16080f42cb68d4---mobupapodasunigur.pdf
    • http://sushimura1.com/uploads/files/wakorarotivi.pdf
    • https://nuregio.de/wp-content/plugins/formcraft/file-upload/server/content/files/160b50b8b58f01---3332689216.pdf
    • http://www.sunarpazarlama.com/wp-content/plugins/super-forms/uploads/php/files/vclhp7qpgkojml3cre1ecp8397/98819965306.pdf
    • https://www.avenueroadadvertising.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607289b6ca49b---11564380101.pdf
    • https://costumeworld.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607de27a576c7---nisopopamidutemazodo.pdf
    • http://www.afamaresme.org/wp-content/plugins/formcraft/file-upload/server/content/files/1607328f6bce58---dowedetonimukozopude.pdf
    • http://www.haztartasigepszakuzlet.hu/pics/file/puripixubexuzevasunadowoj.pdf
    • https://amenagementsoleil.com/wp-content/plugins/formcraft/file-upload/server/content/files/16077b33287526---58231446768.pdf
    • http://actionelectric.pt/www/wp-content/plugins/formcraft/file-upload/server/content/files/160b35af6c4a90---81135808366.pdf
    • https://carthink.org/wp-content/plugins/formcraft/file-upload/server/content/files/160b2d8260579d---16674722427.pdf
    • http://a-range.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160a07aff77f8a---badeteguxakefujumasoko.pdf
    • http://bjaimama.com/data/upload/2021/05/file/202105231121347372.pdf
    • https://chefinhogourmet.com/wp-content/plugins/super-forms/uploads/php/files/bc482fe5d96a8cbe3fcfa83056f7ef11/35902849775.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/YTWXjIUwRh0/uplcv?utm_term=the+hindu+astrology+in+tamil
    • 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_002_off0001a3f5.bin
4eb415e0aa43b4a5170e5815fd3175c483543d9a615971eb454837ee9cdc54f4		 decompressed-pdf-stream PDF FlateDecoded stream at offset 0x1A3F5 30800 bytes
font_01_sfnt_off0001dd13.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1		 pdf-font-stream PDF embedded font (sfnt) at offset 0x1DD13 16792 bytes
font_02_sfnt_off0001f525.bin
27beed7706f3f4226433065bc95fb2942c4dfc29b57037e6477c0c931ca39c53		 pdf-font-stream PDF embedded font (sfnt) at offset 0x1F525 23636 bytes
font_03_sfnt_off00022dd8.bin
27ca3976913f83b7b16df0aea924c43e913755a3e8931818d092138c3795aa60		 pdf-font-stream PDF embedded font (sfnt) at offset 0x22DD8 10872 bytes

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