Malicious PDF — malware analysis report

Static analysis result for SHA-256 b6d494b08a1515b7…

MALICIOUS

PDF

79.0 KB Created: 2021-09-08 06:01:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: e558af666bf405c06aa85f89048be642 SHA-1: e391e17a753d64fe18928e9781534d79abe21cdc SHA-256: b6d494b08a1515b72d093d4232e79a1a837b3f6ae547e9f8759dae908652f29e
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF was flagged by ClamAV as Pdf.Phishing.Trojan and ML classifiers, indicating malicious intent. It functions as a link farm, with numerous URLs pointing to compromised CMS uploads and disposable hosting, suggesting an attempt to distribute malware or engage in phishing. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9933

Heuristics 6

  • 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 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://tsg-edinstvo.ru/userfiles/file/joxagiwikotulit.pdf In PDF document text
    • http://wsystem.sk/userfiles/files/tosumapaxabiwupuwelabiv.pdfIn PDF document text
    • http://www.dnevi-sekretarjev.eu/wp-content/plugins/formcraft/file-upload/server/content/files/16093d390d6dad---60704048658.pdfIn PDF document text
    • http://bscartridge.com/pic/gapatomegafuwakukijax.pdfIn PDF document text
    • https://www.actionconstructionjax.com/wp-content/plugins/super-forms/uploads/php/files/f3343df24f302bdaabeddf0e3ab4e8d1/71122728033.pdfIn PDF document text
    • https://ipcare.nl/wp-content/plugins/super-forms/uploads/php/files/5hkjovvpd1rejq6v01mkch6j8d/xosanavajefox.pdfIn PDF document text
    • http://fonnepal.org/userfiles/file/mupepe.pdfIn PDF document text
    • https://markyatirim.com/resimler/files/64569471670.pdfIn PDF document text
    • https://arbormaster.net/uploads/files/wawevinavufutuxifizikena.pdfIn PDF document text
    • https://history.tlshaa.org.tw/ckfinder/userfiles/files/30861051895.pdfIn PDF document text
    • https://40parables.com/wp-content/plugins/super-forms/uploads/php/files/3da3a1ba46a83312922d4a24cac4020b/magakakazimapujugomunab.pdfIn PDF document text
    • https://pinpointfeedtech.com/ckfinder/userfiles/files/24528035112.pdfIn PDF document text
    • http://progettogeometra.it/userfiles/files/63169616530.pdfIn PDF document text
    • https://mecaniquekd.ca/upload/file/gepogavuzolutifi.pdfIn PDF document text
    • https://stepweystudy.com/ckfinder/userfiles/files/dibisolasizof.pdfIn PDF document text
    • http://boschvietnam.com/files/usersfiles/files/tidalogegeximirufamufudu.pdfIn PDF document text
    • http://jtour.vn/userfiles/file/kegutelukugowimas.pdfIn PDF document text
    • http://sarahscupcakery.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608f474f76f25---kusojiweroveg.pdfIn PDF document text
    • https://www.changhuapmo.org/plugin/ce1/ckfinder/userfiles/files/nugokewudorajemux.pdfIn PDF document text
    • https://middletonchambers.com/ckfinder/userfiles/files/83133795752.pdfIn PDF document text
    • http://asesorialuishervas.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a8c99518d47---54894185375.pdfIn PDF document text
    • http://geteffective.biz/uploadfiles/file/1925572066.pdfIn PDF document text
    • https://call-life.com/ckfinder/userfiles/files/47165045926.pdfIn PDF document text
    • http://dighakanchaninternational.com/FCKeditor/file/temajenasepejireji.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/YTWXjIUwRh0/uplcv?utm_term=aquaculture+books+in+telugu+pdfPDF 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000b671.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB671 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ce83.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCE83 18896 bytes
SHA-256: 5b614538b347db5180844c554efa5460529293d70f7ba3efa16419e0f67862b4
font_02_sfnt_off0000ff1e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF1E 11252 bytes
SHA-256: be71aa2562c2b318fef869b099376213d3af95aebb8e82bfcb678f188613a2a9
font_03_sfnt_off000118ee.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x118EE 16060 bytes
SHA-256: 64af0185a2beffa7382febdf957b2ddd2015d3985e5bc97cf8ad64f3c2914973