Malicious PDF — malware analysis report

Static analysis result for SHA-256 b528c126298729e7…

MALICIOUS

PDF

90.6 KB Created: 2021-02-25 21:33:27 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-16
MD5: e4f88f3b9ede4b9c688f79c1d828cc66 SHA-1: 260877bde2b44bbe4858da6ed27931da762ebf10 SHA-256: b528c126298729e7332b62f79910646dfc5a0526cfd22b15b272f87af9b3e064
274 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript T1203 Exploitation for Client Execution

This PDF file was flagged as malicious by multiple heuristics and a machine learning classifier, indicating a high likelihood of malicious intent. It contains numerous links to redirector infrastructure, specifically pointing to 'crophysi.ru', which is associated with phishing and SEO link farms. The document body, though heavily obfuscated, contains metadata suggesting it was generated by wkhtmltopdf, a tool often used to create SEO-optimized content for malicious purposes. The presence of these elements strongly suggests the file is designed to lead users to malicious sites, likely for credential harvesting or further malware delivery.

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 links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • 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.
  • Image lure linking to an SEO redirector (free-download phishing) high PDF_SEO_UTM_REDIRECTOR_LINK
    PDF embeds an image with little or no body text and a clickable link to a multi-word utm_term / FeedBurner-proxied SEO redirector — the 'free ebook / solution-manual / document download' phishing family that ranks for natural-language search queries and routes the user into a payload/redirect chain. The PDF carries no exploit; the risk is the linked destination. Flagged structurally (image lure + SEO redirector) so it does not depend on a ClamAV/ML signature, and regardless of how many filler text pages the lure carries.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) or Microsoft license-boilerplate documents that carry no urgency or charge/dispute escalation.
  • 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://crophysi.ru/award?keyword=dell+optiplex+960+diagnostic+lights+3+4 In PDF document text
    • https://cdn-cms.f-static.net/uploads/4377407/normal_6027c38d4ec6e.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4417327/normal_6033016209253.pdfIn PDF document text
    • https://livubefelamujir.weebly.com/uploads/1/3/4/8/134899239/6984271.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4481168/normal_5fe3e66129afa.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4414500/normal_5fff3eb540905.pdfIn PDF document text
    • https://revawowi.weebly.com/uploads/1/3/5/3/135317167/ef40cee1bb11db.pdfIn PDF document text
    • https://fevowavekotaxuw.weebly.com/uploads/1/3/4/6/134635114/bfd6b.pdfIn PDF document text
    • https://wevapagavum.weebly.com/uploads/1/3/4/3/134306171/dab8c85d851.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4480383/normal_5fecbb3c8e4ad.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4404503/normal_60339337b59da.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/wipotegadodorek/electromagnetic_waves_spectrum_worksheet.pdfIn PDF document text
    • https://s3.amazonaws.com/rovikibixu/39735251703.pdfIn PDF document text
    • https://s3.amazonaws.com/viwoxuz/highlights_hidden_pictures_answers_august_2018.pdfIn PDF document text
    • https://s3.amazonaws.com/puretulenuza/kopinutidobeduxojosejoro.pdfIn PDF document text
    • https://s3.amazonaws.com/fenatagazise/filmorago_video_editor_free.pdfIn PDF document text
    • https://s3.amazonaws.com/tozaduliwubega/cross-_validation_rule_violation_report_r12.pdfIn PDF document text
    • https://s3.amazonaws.com/kawotexulozax/nazijapurujemoma.pdfIn PDF document text
    • https://s3.amazonaws.com/xezonijida/vlookup_excel_example.pdfIn PDF document text
    • https://s3.amazonaws.com/mizeteb/56251701660.pdfIn PDF document text
    • https://s3.amazonaws.com/jotizifime/intertherm_mobile_home_electric_furnace_parts.pdfIn 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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000123cb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x123CB 6012 bytes
SHA-256: 62d85a823a73d77e8b49b13047e72ad068df53d26adb3aed833116ec83ed6c91
font_01_sfnt_off0001384a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1384A 11308 bytes
SHA-256: 4dfc1e987dc7642b814e0372c5430f1ef5669cafbcfd59168f242f6da695f15a