Malicious PDF — malware analysis report

Static analysis result for SHA-256 cb78d4d6deb9ab64…

MALICIOUS

PDF

83.1 KB Created: 2021-09-07 07:46:50 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: fe44342116fb12b7f78b9e5bc2311454 SHA-1: 8f21d5d79297a13e4db7ef684a8d30c1100eecc1 SHA-256: cb78d4d6deb9ab64737ba2de3dee2271ac45a6d20b9a46e3ee3460eea33c797a
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous links to external websites, many of which are hosted on compromised or disposable domains, suggesting a phishing or malware distribution campaign. The presence of PDF-specific heuristics related to URI and link farms further supports this. No scripts were extracted, but the overall structure and URL patterns are consistent with a malicious PDF designed to redirect users to harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

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 https://krisoc.ru/uplcv?utm_term=virtual+lab+the+cell+cycle+and+cancer+answers+pdf
    • http://aligokdemir.com/resimler/files/94049567861.pdf
    • http://ceramkgres.ru/userfiles/file/90042939957.pdf
    • https://willmarareachamber.com/ckfinder/userfiles/files/wawokerafebefugan.pdf
    • http://goreskyreunion.com/clients/b/ba/ba087d28c24afe6c5bc45fa062332e47/File/20304170453.pdf
    • https://www.chesapeake-lighting.com/wp-content/plugins/super-forms/uploads/php/files/259730b63c57c55184ac29c472b46e93/73623155354.pdf
    • http://kazenergy.kz/wp-content/plugins/formcraft/file-upload/server/content/files/1607a6819430ee---wibowuvowebedigineposasi.pdf
    • http://pengyou-english.com/FileData/ckfinder/files/20210728_CD8D328613FCE571.pdf
    • http://capital96.com/userfiles/file/66022428889.pdf
    • http://arniestribu.com/campannas/file/96509618009.pdf
    • http://pericosrentcar.com.mx/wp-content/plugins/formcraft/file-upload/server/content/files/16099f918af801---7488509759.pdf
    • https://www.budgetskemaet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/160944c82207a5---petusiluxonaziruwufi.pdf
    • http://aaaexpressac.com/userfiles/file/98608817932.pdf
    • http://littlepearlbooks.in/data/eimages/file/16002681361.pdf
    • http://investin-khj.ir/ckfinder/userfiles/files/tatisaliwinewabapiki.pdf
    • http://pvsystreports.com/wp-content/plugins/super-forms/uploads/php/files/2te0u0c9n2r4vvsqj2cl0ou2r5/xalum.pdf
    • http://rydelko.pl/userfiles/file/49580705555.pdf
    • http://reicar.dk/userfiles/file/wetubagimolezuw.pdf
    • https://autotrilogy.com/wp-content/plugins/super-forms/uploads/php/files/1ffd135b683b2a4b347651d6e665f3d3/58861658947.pdf
    • http://aarogyamedico.com/userfiles/file/bopokaf.pdf
    • https://hashtag.school/userfiles/file/sewopemow.pdf
    • https://shining4u.com/wp-content/plugins/super-forms/uploads/php/files/04b130cdca09cd4b7e45ae6dfb49ad54/35024573176.pdf
    • https://aryaayur.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a0b293a9815---1795279232.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_off0000df6b.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xDF6B 16792 bytes
font_01_sfnt_off0000f77d.bin
8163ae261ce01fbedf19e88abf3b6ed1716366a0f56631efdd52640590f8c1bd
pdf-font-stream PDF embedded font (sfnt) at offset 0xF77D 17860 bytes
font_02_sfnt_off0001255f.bin
fb37e5dcac1e995e64f28e432bf7f192a7dff3391bc0fabaebc78f0cb6e55f36
pdf-font-stream PDF embedded font (sfnt) at offset 0x1255F 11008 bytes