Malicious PDF — malware analysis report

Static analysis result for SHA-256 5558ddb811cc24be…

MALICIOUS

PDF

85.2 KB Created: 2021-09-06 16:24:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 2410051e2eeb037d8f4176f3f49ad915 SHA-1: 7c2e5f9417fc31ae02298bcacb4d2054f497effb SHA-256: 5558ddb811cc24be8dd8c84ec34f2156c09ae28a89f8c4998b23e7c0ae2dd97e
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file that contains numerous links to external websites, many of which are hosted on compromised WordPress installations or disposable domains. The ClamAV detection and ML classifier strongly indicate malicious intent, likely for phishing or distributing further malware. The presence of PDF_RANDOM_URL_LINK and PDF_SEO_DISPOSABLE_LINK_FARM heuristics further supports the conclusion that this PDF is designed to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9860

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 http://veterina-hrib.cz/user-uploads/files/wegaxifedodibamemejure.pdf In PDF document text
    • https://inclinedigital.com/wp-content/plugins/formcraft/file-upload/server/content/files/16091d45fa9843---71203593310.pdfIn PDF document text
    • https://morethancleaningservices.com/wp-content/plugins/super-forms/uploads/php/files/aad04cd424eb16f553c1a1287738e121/vunarizerixekideliji.pdfIn PDF document text
    • http://londonjip.com/userData/board/file/putakatobikupej.pdfIn PDF document text
    • http://www.1atlanticfunding.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608ef843cc1eb---40670970327.pdfIn PDF document text
    • https://dazzlin.co.uk/wp-content/plugins/super-forms/uploads/php/files/ecb87610698d6a65393e847748c69417/45708645465.pdfIn PDF document text
    • https://lisacutler.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ae3590534b6---jopatesuwudere.pdfIn PDF document text
    • http://longthinhphat.net/uploads/files/75390994355.pdfIn PDF document text
    • https://na-nule.ru/wp-content/plugins/super-forms/uploads/php/files/c6qh4ooa4bqt4nlbrcd0aip986/87687507967.pdfIn PDF document text
    • http://andrenickels.de/ckfinder/userfiles/files/gadowawetetozedogejowu.pdfIn PDF document text
    • https://newshieldinsurance.com/demo/gsa/final/images/file/73314021700.pdfIn PDF document text
    • http://terapie-psi.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160944e49a98e4---xalitijo.pdfIn PDF document text
    • https://defrokatilai.lt/images/files/jisaluzanefafepibegudo.pdfIn PDF document text
    • http://firmykominkowe.pl/Obrazki/edytor/file/90415173946.pdfIn PDF document text
    • https://coimbatorepressclub.com/FCKeditor/userfiles/file/5563736813.pdfIn PDF document text
    • https://benchmarktransitions.com/wp-content/plugins/formcraft/file-upload/server/content/files/160778b0919bd0---dalefavasonevanesufisi.pdfIn PDF document text
    • http://villaturri.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a23454160b0---78314583827.pdfIn PDF document text
    • http://lbtech.kr/upfile/files/jikejovavowefu.pdfIn PDF document text
    • https://pearproperties.in/userfiles/file/6166087570.pdfIn PDF document text
    • http://www.sunargrup.com.tr/wp-content/plugins/super-forms/uploads/php/files/5d00uj9lmo8d0j9th8sah69ud1/nelokirof.pdfIn PDF document text
    • http://www.sunarnuricomuisvealisverismerkezi.com/wp-content/plugins/super-forms/uploads/php/files/u8020hp6t435ot3a7chl85opg5/warujilutokowituf.pdfIn PDF document text
    • https://nobleanimalsanctuary.org/wp-content/plugins/super-forms/uploads/php/files/tmp/dorif.pdfIn PDF document text
    • http://julieesteban.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ac001e38a76---67739531758.pdfIn PDF document text
    • https://festivalecolo.ca/wp-content/plugins/formcraft/file-upload/server/content/files/160ecd72007834---88202711152.pdfIn PDF document text
    • http://inezorviskids.com/clients/37546/File/nemajegavunebekava.pdfIn PDF document text
    • http://kazenergy.kz/wp-content/plugins/formcraft/file-upload/server/content/files/1612b1731e6ef0---wugagake.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/6naE_Nh8_CY/uplcv?utm_term=notability+pdf+importPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e4ab.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4AB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000fcbd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFCBD 20384 bytes
SHA-256: 5158d52f7dd42d49eb39e7de50e4e343cfc4c4f1f76c2d509ecf12a0e2d4ac1a
font_02_sfnt_off00012fd8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12FD8 10484 bytes
SHA-256: 1778995ff0a1dc0c4766e425312a19c78d64a9b9b608f46603ab17994e6c1009