Malicious PDF — malware analysis report

Static analysis result for SHA-256 f83f5dab129fca07…

MALICIOUS

PDF

70.1 KB Created: 2021-06-30 03:34:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 723702f50844d9de99643ae9eb8c1ca3 SHA-1: fe22435fb8d852b415e0871e8cb12e2361b3a0ad SHA-256: f83f5dab129fca07465a03160580e391f7452f0c04f396c2de84b32569d24722
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains numerous embedded links, many pointing to compromised WordPress upload directories, suggesting a phishing or malware distribution campaign. The ML classifier and ClamAV detection strongly indicate malicious intent. While no scripts were explicitly extracted, the presence of PDF_URI and PDF_RANDOM_URL_LINK heuristics suggests the document is designed to redirect users to potentially harmful external resources.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

Heuristics 7

  • 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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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=initialize+two+dimensional+array+c
    • https://www.etbsupplies.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a6cf0e5fb2a---57121320453.pdf
    • http://kraljicabih.com/wp-content/plugins/formcraft/file-upload/server/content/files/160828fa8923e4---tuveriwemejuwufuvetagu.pdf
    • https://pilotcenter.gr/wp-content/plugins/super-forms/uploads/php/files/1hvfafdljuo9gmoucq2kkihc73/jusilusegi.pdf
    • https://firsatpin.com/calisma2/files/uploads/29103209475.pdf
    • https://kes-stv.ru/wp-content/plugins/super-forms/uploads/php/files/b6a022aa611fd2265aae22769a2a5974/72632908142.pdf
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a6f0939295d---94349962643.pdf
    • http://gerd-pollak.de/userfiles/file/lipebigovagefuzugitadewav.pdf
    • https://www.kasekimi.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f7fe1ee155---kaxemew.pdf
    • https://aliencosmicexpo.com/wp-content/plugins/formcraft/file-upload/server/content/files/160acfcc999427---38952480749.pdf
    • http://elenasteele.com/wp-content/plugins/formcraft/file-upload/server/content/files/160960938d4952---notibixu.pdf
    • http://www.pirac.org/wp-content/plugins/super-forms/uploads/php/files/7210d1c513e9361d03d63bfb14ceb549/wanonidibomabesolowejusup.pdf
    • http://peusch.lu/userfiles/files/73350981980.pdf
    • http://keramann.ru/uploads/files/nepawikojuv.pdf
    • http://arcomproltd.com/userfiles/file/dutizoxedawuruxisenut.pdf
    • http://www.sunarnuricomuisvealisverismerkezi.com/wp-content/plugins/super-forms/uploads/php/files/quda2faj13b95fvp506g0ensr5/43457871771.pdf
    • https://www.movingwithmagna.com/wp-content/plugins/super-forms/uploads/php/files/d0c2061c38263d7c2b4eef0ed4de6c8a/jopitedilapuxadesopow.pdf
    • https://amiablediamonds.com/wp-content/plugins/super-forms/uploads/php/files/13d46816d8bd9327447a2a85ad24f6a8/3198834748.pdf
    • https://robotics-institute.com/wp-content/plugins/super-forms/uploads/php/files/l4enr2ssn6b9ak7btjdeegqga0/lifetozalodemidamugit.pdf
    • https://italvaping.com/file/22075664954.pdf
    • https://rffsev.ru/wp-content/plugins/super-forms/uploads/php/files/126a11595cb39e635a95ec997e8337fd/susexavab.pdf
    • https://www.colegiodesafio.net/home/wp-content/plugins/formcraft/file-upload/server/content/files/1609260246737c---64286558001.pdf
    • http://audiencefertilization.com/fckeditor/editor/filemanager/connectors/php/userfiles/file/pubetekasojunadavud.pdf
    • http://www.vitrierbxl.be/wp-content/plugins/formcraft/file-upload/server/content/files/1608a05c5d0c28---wuvob.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_off0000b424.bin
04710f9c750f48dc7db644d7d9f8d7423bb66b261a5b0a949e51ed12592ca563
pdf-font-stream PDF embedded font (sfnt) at offset 0xB424 14868 bytes
font_01_sfnt_off0000da5b.bin
a341bd209209dbee85f5bf82117c25974def5cf1e6ef2b25bbb06367b5d42c98
pdf-font-stream PDF embedded font (sfnt) at offset 0xDA5B 10744 bytes
font_02_sfnt_off0000f328.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF328 16792 bytes