Malicious PDF — malware analysis report

Static analysis result for SHA-256 c35e8dcf23888057…

MALICIOUS

PDF

81.5 KB Created: 2021-08-28 21:50:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: bba8973487cf2ebf6a15419555c70354 SHA-1: 6f690eda2dee5c0d9a15223d7ad334f4982eb6cb SHA-256: c35e8dcf238880575d35b8c4439470be2f568a1485ee79258950994bc8bf8e35
172 Risk Score

Malware Insights

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

The PDF contains numerous external links, many pointing to compromised CMS uploads or disposable hosting, suggesting a link farm for SEO manipulation or phishing. The embedded JavaScript stream and the ClamAV detection further indicate malicious intent. The document body is heavily obfuscated and unreadable, providing no direct content-based clues.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9987

Heuristics 8

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Urgency / deadline lure low SE_URGENCY_LURE
    Document contains urgency or deadline language ('account will be terminated', 'action required within 24 hours', etc.) — useful context, but low-signal without other findings
  • 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://krisoc.ru/uplcv?utm_term=probability+questions+and+answers
    • http://progfin.pl/userfiles/file/sadulisaju.pdf
    • https://narimasu-chintai.net/jcfiles/file/41931137875.pdf
    • https://hcs1000.org/wp-content/plugins/super-forms/uploads/php/files/e499077c3a9e131e68306764c9af03e3/66435069098.pdf
    • http://vegasoft.hr/wp-content/plugins/formcraft/file-upload/server/content/files/16077329f8d376---seduwuzitefagabaxurikupu.pdf
    • http://amandamaitland.com/images/file/82077454614.pdf
    • http://baliretreatcenter.com/olabali_ci/media/images/newsfiles/53027526293.pdf
    • http://iwish-cosmetics.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609d4d392233b---26118056011.pdf
    • http://webmba.fr/client/logo/file/bilexiwepojotaxeremu.pdf
    • http://hurtglass.pl/upload/file/dowekusiru.pdf
    • https://feriaesotericadeatocha.com/wp-content/plugins/formcraft/file-upload/server/content/files/160de0c89b55e5---33454824997.pdf
    • https://glosunspa.com/wp-content/plugins/formcraft/file-upload/server/content/files/16096a3cab6b69---menuletifomirivebir.pdf
    • http://sentralperdana.com/file/31741748216.pdf
    • http://optimus.org.au/wp-content/plugins/formcraft/file-upload/server/content/files/16094d7e506380---67313438762.pdf
    • http://objetivovender.com/wp-content/plugins/formcraft/file-upload/server/content/files/161122a24a5a1a---46441387304.pdf
    • https://trichynext.com/wp-content/plugins/super-forms/uploads/php/files/82136ffdf8a99125b8cc003431732a37/zujonenozunepipik.pdf
    • http://spearsyounglegacy.com/clients/b/b2/b2c23f164518415ec8f3c1c8d0af542d/File/45336592767.pdf
    • http://for-rent-aalst.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607be08293ff3---pibinagirixuwikiwa.pdf
    • https://mlbcsimleague.com/ckfinder/userfiles/files/fewukofa.pdf
    • http://wakingbeauty.com/wp-content/plugins/formcraft/file-upload/server/content/files/16103f0e0e7bfd---zozeziv.pdf
    • http://hrt-foto.hu/_user/file/27972161870.pdf
    • http://www2.grupoksl.com.br/js/ckfinder/userfiles/files/wonasusewuronexejiniwufa.pdf
    • http://lifestyleufa.ru/wp-content/plugins/super-forms/uploads/php/files/15d75bff9f38add8b1f25ee22cd0813a/91165676618.pdf
    • https://jpjplumbingandheating.com/FCKeditor/file/1351473025.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_off0000d945.bin
51abdc05efeb46293f610a96d1ed049608f9ccedfc7e5520ba41ead743248261
pdf-font-stream PDF embedded font (sfnt) at offset 0xD945 17412 bytes
font_01_sfnt_off0001068e.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x1068E 16792 bytes
font_02_sfnt_off00011ea5.bin
409ed1bdf914091f75b41576ff81cbb91e6bfb4de0c334a912b712ea6451ff23
pdf-font-stream PDF embedded font (sfnt) at offset 0x11EA5 10828 bytes