Malicious PDF — malware analysis report

Static analysis result for SHA-256 ef8855b7e7bc9caf…

MALICIOUS

PDF

78.9 KB Created: 2021-06-13 09:47:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-05
MD5: 35137af890cee5903e201a10f30a53d4 SHA-1: 0c67f0765558a30364a39612c212cc12e1d58a48 SHA-256: ef8855b7e7bc9caf294ec5640f57e90e5ed527a1a0a3a597641d7f60b3ef5ae3
164 Risk Score

Malware Insights

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

This PDF document was flagged as malicious by ClamAV and an ML classifier. The file embeds a large number of external links characteristic of an SEO link farm, many hosted on compromised CMS upload directories and presents a deceptive download button. Specific URLs and indicators for this sample are listed in the indicators section.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://coretry.ru/uplcv?utm_term=physical+fitness+certificate+format+for+job PDF link annotation
    • https://saraelv.no/wp-content/plugins/formcraft/file-upload/server/content/files/160706a46608ff---tajepulujemevuwufufovikaj.pdfIn PDF document text
    • https://selectwifi.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c1faaa0f9d0---58236167158.pdfIn PDF document text
    • https://www.taxikladis.gr/wp-content/plugins/formcraft/file-upload/server/content/files/1608475f545680---lakazuvelulifevudunu.pdfIn PDF document text
    • https://discoverapartmentsforrent.com/wp-content/plugins/super-forms/uploads/php/files/e36459112ea49c40622d5966a52ca3ce/disutavomifiminobax.pdfIn PDF document text
    • https://www.vigo.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160bfe76011364---63826476954.pdfIn PDF document text
    • https://htchninc.com/d/files/33809666591.pdfIn PDF document text
    • http://akbmodel.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b351f038f55---39698296265.pdfIn PDF document text
    • https://belgradenightlife.info/wp-content/plugins/super-forms/uploads/php/files/7a1kkihi24uashi3df8pq9d800/famupubobe.pdfIn PDF document text
    • https://www.finestkindcharter.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608398a7f191c---vomasirovujobokir.pdfIn PDF document text
    • https://www.allterra.group/wp-content/plugins/super-forms/uploads/php/files/92832c8ae62ad3819188cb93d17bfe3f/10352028930.pdfIn PDF document text
    • https://dongytueduc.com/wp-content/plugins/super-forms/uploads/php/files/jmak75rftg8an90nr0llo0mv7h/46068026401.pdfIn PDF document text
    • http://www.kzhep.in.ua/wp-content/plugins/super-forms/uploads/php/files/29spg7m70jdfkp2plmb9ht76f5/vovokofuwad.pdfIn PDF document text
    • http://bagumul.com/file_upload/spaw_upload/file/20210518184556.pdfIn PDF document text
    • https://eandjfamilyhealthcenter.com/wp-content/plugins/super-forms/uploads/php/files/5c15e4efb133957cf48d509658f09857/venumivumefom.pdfIn PDF document text
    • https://ltanimalpark.com/wp-content/plugins/super-forms/uploads/php/files/e830b401e6f4c70f1a8dab8138402d81/petifegixifupatum.pdfIn PDF document text
    • https://marksiegeldds.com/wp-content/plugins/super-forms/uploads/php/files/442197da51709d85ea0424db6fb34a99/4061214171.pdfIn PDF document text
    • http://www.alfainstal.pl/wp-content/plugins/formcraft/file-upload/server/content/files/1607119a332446---lozevisesarudar.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • 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://scripts.sil.org/OFLIn 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_off0000df71.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDF71 5440 bytes
SHA-256: 8d64d1d097f21704dc4d78a918f6bcfe675c0404a05901f9cc4855fe673e4191
font_01_sfnt_off0000f1d9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF1D9 10812 bytes
SHA-256: a9369a98b49466f18416ab095edee1e5596cd29d758f5bdc32ffc186aadd4353
font_02_sfnt_off00011720.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11720 16172 bytes
SHA-256: 6e699eab9a6fef16b3ea923df7b93ce1c5cbd97c7a594d359cd98c90be4a35f1