Malicious PDF — malware analysis report

Static analysis result for SHA-256 bd1abcc6f846e71f…

MALICIOUS

PDF

75.2 KB Created: 2021-05-02 13:15:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-23
MD5: ee87f168428982b4d2b5b2bda8396937 SHA-1: f66ebc8806fee5faadfe3a73572f374e927ed681 SHA-256: bd1abcc6f846e71fc02afc9535c2f89cded1128c7cd24046b5ee92ad71595828
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF contains a link farm pointing to multiple compromised WordPress sites, which in turn host PDF files. These PDFs likely serve as lures to trick users into downloading a malicious APK, as suggested by the 'bithumb singapore apk' string found in the document body. The ML classifier strongly flagged this PDF as malicious, supporting the assessment of a malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • 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://ecoinkworld.com/wp-content/plugins/super-forms/uploads/php/files/2b89eeda2c8c724566c04a0244f9a5ee/jikukevef.pdf In PDF document text
    • https://medok18.ru/wp-content/plugins/super-forms/uploads/php/files/aa5060f5a566b1f764d0906a4e1bb49b/kolixuvabigafisume.pdfIn PDF document text
    • http://www.pirac.org/wp-content/plugins/super-forms/uploads/php/files/97dcdfa93cd3583fe781bc95268e2e93/14982343990.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607dbac158163---mexofan.pdfIn PDF document text
    • https://landlorddebtadvisory.com/wp-content/plugins/super-forms/uploads/php/files/1572mfmcmpv0k8ofvp7g5rvke1/64412897207.pdfIn PDF document text
    • http://victorylimo1.com/wp-content/plugins/formcraft/file-upload/server/content/files/16078860ad83d9---zijezukad.pdfIn PDF document text
    • https://www.vedaaz.com/wp-content/plugins/super-forms/uploads/php/files/2b2b4050795de75deae48acdca3b6a3e/43971530846.pdfIn PDF document text
    • https://www.geosuiteonline.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607166a4efd0b---finameluzapudufiwilenegop.pdfIn PDF document text
    • https://vernadoc.com/wp-content/plugins/super-forms/uploads/php/files/ddaca9df0b0d49c5061b80e5be6c1bd0/bodudusivisa.pdfIn PDF document text
    • https://www.cibaospalaser.com/wp-content/plugins/super-forms/uploads/php/files/hgjrcjbue35d5b2um5im3fv502/gesuzetubazonu.pdfIn PDF document text
    • http://willtorock.com/wp-content/plugins/formcraft/file-upload/server/content/files/160898f8031b4d---zuzitiminesu.pdfIn PDF document text
    • http://allprintusa.com/admin/images/file/tonosabujitibolubox.pdfIn PDF document text
    • https://cbolean.com/wp-content/plugins/super-forms/uploads/php/files/83qiq8kmfqvf6t15ikhn1oc270/1118725112.pdfIn PDF document text
    • https://www.ideaklinikbakirkoy.com/wp-content/plugins/formcraft/file-upload/server/content/files/16075803cb8785---silavenafunaberida.pdfIn PDF document text
    • http://ampletrekking.com/userfiles/file/fiwebo.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BkSY9tpko7c/uplcv?utm_term=bithumb+singapore+apkPDF 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://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_off0000d109.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD109 5452 bytes
SHA-256: 4b13d47d6479616da7ffa972689abfee40ec381d92a7fa0d059ead31a9902646
font_01_sfnt_off0000e367.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE367 11276 bytes
SHA-256: 5eade68681932d58b4d4e0b5537849ecc8438a30a1150231950f9867befe8111
font_02_sfnt_off00010a6b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A6B 16168 bytes
SHA-256: 794d8cc090a449e0d460036171b2d5b2c749cb0dc3f17972c44626ada68ee3d8