Malicious PDF — malware analysis report

Static analysis result for SHA-256 21f8df82a2ab1a47…

MALICIOUS

PDF

75.0 KB Created: 2021-04-01 18:30:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-10-23
MD5: c1d297a8e9f6c57737aff2c3b5eef4fa SHA-1: 8c16c21efb336bf021fa3d240ff13969928a12f3 SHA-256: 21f8df82a2ab1a47ce74efe7e3a9bc35604ab7408575c54d2c7b727a8b24a563
186 Risk Score

Malware Insights

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

The PDF file was identified as malicious by ML classifiers and ClamAV, specifically flagged as a phishing trojan. It contains a large number of external links, many pointing to other PDF files, suggesting a link farm or SEO manipulation tactic. The primary URL observed is 'https://xajibur.ru/award?keyword=barbara+ann+brennan+libros+pdf', which is likely part of the distribution or redirection chain.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://xajibur.ru/award?keyword=barbara+ann+brennan+libros+pdf PDF link annotation
    • https://static.s123-cdn-static.com/uploads/4404310/normal_5ffcb3c828c6d.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4375341/normal_5ff4d20f4d46f.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4449600/normal_5fe9dd77a1a29.pdfIn PDF document text
    • https://dekajemo.weebly.com/uploads/1/3/1/4/131453049/fovoravukurosep-kuzada.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4408588/normal_6046d9d1bed81.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4417805/normal_600fb5fbed303.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4386839/normal_6005efd54719a.pdfIn PDF document text
    • http://afracheat6.xyz/28364783214d89hy.pdfIn PDF document text
    • http://oneitstore.info/55143733734dpa1h.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4413004/normal_60144a00258a0.pdfIn PDF document text
    • http://clubstore.pro/mixing_eq_cheat_sheetyj6yr.pdfIn PDF document text
    • https://gunobapeve.weebly.com/uploads/1/3/4/7/134706327/nafepudevawafala.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4372735/normal_604e20a598d44.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4446289/normal_6001a34fa2995.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4454575/normal_5fe9b969494f6.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4420902/normal_5fdc53929f75a.pdfIn PDF document text
    • http://finansi-7.online/gm_motors_diet_plan_day_3laje3.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4453144/normal_6053519fd04fc.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • https://01d67eed-50ba-4ccb-8f82-c1581f7ed07e.filesusr.com/ugd/e3325f_7384ba54c9e149119f561249a76fbfda.pdf?index=trueIn PDF document text
    • https://50bf384a-eeac-4f26-a262-e2ba1a5e00ba.filesusr.com/ugd/17159d_540779efe5914b83a7f7409567de4205.pdf?index=trueIn PDF document text
    • https://858e1da1-ad31-4e5b-aec0-89c59c6c71f6.filesusr.com/ugd/6240f8_c68079028d574f10823b2812e67200d4.pdf?index=trueIn PDF document text
    • https://983c8978-ad56-435f-a988-47358aa6040c.filesusr.com/ugd/06a663_3acbd977c7d840a79b3537c84caf4e8b.pdf?index=trueIn 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

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d904.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD904 4932 bytes
SHA-256: 3b645ecab94da32b521f2b10a3c056277455c8a9cb2aea695798b4cc3d945a21
font_01_sfnt_off0000e9c0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE9C0 11580 bytes
SHA-256: da9ffdec83a56685cd9a753e48400a6ae9bf2100462dab22df076be2337b0327
font_02_sfnt_off00011013.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11013 4324 bytes
SHA-256: 05d2457133b820fa77aa358e30e9acfbad3f04c46ced9a37296d9311117db176