Malicious PDF — malware analysis report

Static analysis result for SHA-256 1ff4c79736f78e7a…

MALICIOUS

PDF

69.7 KB Created: 2020-11-30 15:39:49 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: f87459a226e85f584c48dc491af5d480 SHA-1: 107e1f7696be6fad845d1c7b5cc69645b0be60e7 SHA-256: 1ff4c79736f78e7a2e54eb96ddd11ac34f7d868c771c8f2ced713046be169f8d
244 Risk Score

Malware Insights

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

The sample is a PDF document identified as malicious by ClamAV and an ML classifier. It contains a large number of embedded links, many of which point to known malicious redirectors or disposable hosting, suggesting a phishing or malware distribution scheme. The document body is heavily obfuscated and contains metadata indicating it was generated by wkhtmltopdf, which can be used to create malicious PDFs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 6

  • 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.
  • 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 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.
  • 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://cctraff.ru/strik?utm_term=mohu+leaf+ultimate+65+channels+list
    • https://vugawijop.weebly.com/uploads/1/3/4/5/134594760/bonobos_bilobevibuno.pdf
    • https://voladivilutefuj.weebly.com/uploads/1/3/4/5/134500748/sufoxejixej.pdf
    • https://fomezesas.weebly.com/uploads/1/3/4/3/134343882/9b556c5df91f.pdf
    • https://xufetujada.weebly.com/uploads/1/3/4/7/134745175/bulojitasilikotatuni.pdf
    • https://miremewokar.weebly.com/uploads/1/3/0/7/130738658/dikegarosazo.pdf
    • https://nudojafobedem.weebly.com/uploads/1/3/1/3/131379550/sutusozupixapu.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://static1.squarespace.com/static/5fc0e940bd14ff0dd29cb4d3/t/5fc13d285147b1480460be60/1606499624801/ways_to_say_mother_family_feud_answers.pdf
    • https://static1.squarespace.com/static/5fbce344be7cfc36344e8aaf/t/5fbdfa60e6d49a06bb5714bb/1606285921388/rupukol.pdf
    • https://s3.amazonaws.com/liwafo/kabaddi_assistant_score_sheet.pdf
    • https://uploads.strikinglycdn.com/files/3d9e27d8-6006-403a-b6be-e119332f8e48/jesinewima.pdf
    • https://static1.squarespace.com/static/5fbce344be7cfc36344e8aaf/t/5fbf5ca93485235c86bdd4af/1606376626086/laredalelawak.pdf
    • https://uploads.strikinglycdn.com/files/d6590fba-03d9-4e8f-803b-0ee896262384/doom_2_mod_apk_free_download.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d061.bin
3c7e83c6a778ff91ad2cbb6f66c9267c1debf7de33a2534654b892c2c930ded6		 pdf-font-stream PDF embedded font (sfnt) at offset 0xD061 5308 bytes
font_01_sfnt_off0000e262.bin
1a736ba824dc5bb1d0efd6ba14da2d32783f869e8fb6215d1311d215771c893d		 pdf-font-stream PDF embedded font (sfnt) at offset 0xE262 11208 bytes

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