Malicious PDF — malware analysis report

Static analysis result for SHA-256 8781a5b83c55cba6…

MALICIOUS

PDF

77.8 KB Created: 2021-09-18 05:33:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 767366c4ac434f751d53b6d7c894931e SHA-1: 32d192347acc9484bdb7d7aa61bc6d4b950d1a61 SHA-256: 8781a5b83c55cba652fac28d6e66d5183755a13a148ed37883a9bb6810ab81d0
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ClamAV and an ML classifier, with heuristics indicating embedded JavaScript and a link farm. The embedded JavaScript, combined with numerous links to potentially compromised sites, suggests an attempt to lure users into downloading further malicious content or visiting phishing pages. The presence of a link farm on disposable hosting further supports a malicious intent for distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 7

  • 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.
  • 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://cissud.it/uploads/ck_editor/files/salolamomiwelinofox.pdf
    • https://mamproducciones.es/wp-content/plugins/formcraft/file-upload/server/content/files/16140777a4180c---42893941141.pdf
    • http://alpinist.store/sribati/editor/uploadfiles/66673602490.pdf
    • http://escolacaritas.com/wp-content/plugins/formcraft/file-upload/server/content/files/161403da176cd0---90276138702.pdf
    • http://quesnelbusinessnetwork.ca/userfiles/file/kufelitogalozenuxid.pdf
    • https://blsautomation.com/ckfinder/userfiles/files/50535915390.pdf
    • https://congnghiepxd204.vn/upload/files/refukiwobadategazisi.pdf
    • http://fge-service.com/userfiles/file/tusuresifurulesako.pdf
    • http://oishisushigd.com/uploads/files/gikafefinifufozisevuxu.pdf
    • https://bakotech.at/uploads/ckeditor/files/55850203009.pdf
    • http://architettotoma.it/userfiles/files/pugoresowepawurapof.pdf
    • http://tindangnhadat.vn/upload/files/77307099074.pdf
    • http://caacoding.net/wp-content/plugins/formcraft/file-upload/server/content/files/1612fbd6a1e7f8---5888916610.pdf
    • https://semangkabiji.com/contents/files/zesewubabajoritixedib.pdf
    • https://www.colegiodomus.com.br/js/ckfinder/userfiles/files/34597440461.pdf
    • http://studiotecnicopinto.it/userfiles/files/589670239.pdf
    • https://www.chablis-gautherin.com/ckfinder/userfiles/files/sofupufunugurejuz.pdf
    • http://www.temaricerca.com/entry2013/admin/ckfinder/userfiles/files/vevivifokuron.pdf
    • https://g-ortho.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1613a2c5cc231e---35523604168.pdf
    • https://luathoanghuy.com/uploads/files/gafimufuweraremawebirofor.pdf
    • https://globalcareerclub.com/FCKeditor/userfiles/file/lulasirazugufanaxewus.pdf
    • http://ylphs.com/ckfinder/userfiles/files/nobetigajegovolaz.pdf
    • http://wf515345.tw/CKEdit/upload/files/39582626011.pdf
    • http://greenglobepms.com/uploads/20254756685.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/YTWXjIUwRh0/uplcv?utm_term=design+and+analysis+of+algorithms+3rd+edition+solution+manual+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_off0000c89a.bin
162e75a098fe57e256626272775e07f69a58cc79c648735a818f21af2462be93
pdf-font-stream PDF embedded font (sfnt) at offset 0xC89A 11332 bytes
font_01_sfnt_off0000e2f1.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xE2F1 16792 bytes
font_02_sfnt_off0000fb03.bin
84e59e26611195f74a94b2e7e801f4483397f8f4fdddc15f8b73a2257010fe97
pdf-font-stream PDF embedded font (sfnt) at offset 0xFB03 17672 bytes