Malicious PDF — malware analysis report

Static analysis result for SHA-256 b721c42e0e0d9043…

MALICIOUS

PDF

91.1 KB Created: 2021-06-26 14:54:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: d71f34ea0161a156bd6d0dec8bdbe8d2 SHA-1: 05020248190b1c530e19dffd61fcbc5226901455 SHA-256: b721c42e0e0d90435cfd0f3ff65a80e60cbaff259cb80dc278ca781b85726155
172 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF containing embedded JavaScript, which is a common technique for executing malicious code. It also features a link farm pointing to multiple compromised WordPress sites, suggesting an attempt to distribute further malware or conduct phishing. The ClamAV detection and ML classifier further support its malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9835

Heuristics 8

  • 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.
  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://pulsrmedia.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607aa8837de99---65458023499.pdf
    • https://gradeagroup.com/wp-content/plugins/super-forms/uploads/php/files/n7mfc6ll35a7r52nm4ste5k2i7/81431714941.pdf
    • https://www.geosuiteonline.de/wp-content/plugins/formcraft/file-upload/server/content/files/160afc12800e94---jojopojuxanaw.pdf
    • http://www.lbf-cosmetics.com/website/wp-content/plugins/formcraft/file-upload/server/content/files/160bd354f32a08---doremesinidukaxatef.pdf
    • https://medgarlci.com/wp-content/plugins/super-forms/uploads/php/files/3b7b1cf31000124a5d3b6d716a7b2637/nekebomijukugujijakik.pdf
    • http://cassotech.nl/site/data/ws/files/89385560726.pdf
    • http://zadonskiy.ru/wp-content/plugins/formcraft/file-upload/server/content/files/160b5bbc9aaa33---rurosunuduzinutiwutota.pdf
    • http://skyrunarser.com/js/fckeditor/editor/filemanager/connectors/php/connector.php/upfiles/file/210605090134244885zp35u3.pdf
    • https://groupburuemas1.com/contents//files/27571531677.pdf
    • https://indacphuc.com/wp-content/plugins/super-forms/uploads/php/files/s5os2q0bvpk7a466u2u4fs3rpe/gebabepopitagatogo.pdf
    • http://manufim.co.il/wp-content/plugins/formcraft/file-upload/server/content/files/1607a4c87540e2---29515828948.pdf
    • https://imad0c0.com/js/ckfinder/userfiles/files/pebilugoberezasororodepa.pdf
    • https://ascinfratech.com/clientprojects/trading/file/35045340441.pdf
    • https://vdbergelectro.nl/wp-content/plugins/super-forms/uploads/php/files/7aa94e3acdf68584c974bd11f0d3d2d5/gapapanukebejipuwaxiko.pdf
    • http://huntland.hu/upload/file/jubikejuverixo.pdf
    • http://www.majorisinvestimentos.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1606c97c35ca3a---nizelilanewanitaw.pdf
    • https://www.servicioscalibrados.com/wp-content/plugins/super-forms/uploads/php/files/191ee5419d768c0e499fec5654ebab44/94832902828.pdf
    • http://worksafeorg.com/wp-content/plugins/super-forms/uploads/php/files/ec3bc7vng4lj9h82mm87f3tct3/4449009320.pdf
    • http://xn--om2b25zm6igqb.com/ckupload/files/sotesamibimemizogo.pdf
    • http://blueyee.com/upload/file/171345232403.pdf
    • http://krindustria.com.br/site/wp-content/plugins/formcraft/file-upload/server/content/files/160ab96d57631f---ronugifuliwejole.pdf
    • http://www.grupohk.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1609d114b64e09---58276160310.pdf
    • https://antoinepanau.com/wp-content/plugins/super-forms/uploads/php/files/03e93007bb883fece580faad71ec92e2/31098430900.pdf
    • http://lumieretvie.com/userfiles/file/92807147231.pdf
    • http://counterreaction.net/wp-content/plugins/formcraft/file-upload/server/content/files/160c22e246200e---xitojuxirukuzowavefuf.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/GLLx1DTH0VQ/uplcv?utm_term=the+age+of+chaucer+in+english+literature+pdf
    • https://sharpspringwww.kinsta.cloud/wp-content/plugins/super-forms/uploads/php/files/d8442a8972a0376732d612c07f423dfb/71846417546.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_off00010267.bin
1e688082ebc5f5aa330ca6438beea75f88d702457c4ed7f1267358d731d8eb98
pdf-font-stream PDF embedded font (sfnt) at offset 0x10267 16700 bytes
font_01_sfnt_off00012d74.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x12D74 16792 bytes
font_02_sfnt_off0001458b.bin
d9f0b0249632dadc68952fa91ad7fa6859a26f9b8fe00c9ff188e2b1228a6ead
pdf-font-stream PDF embedded font (sfnt) at offset 0x1458B 10960 bytes