Malicious PDF — malware analysis report

Static analysis result for SHA-256 7a235c21c3f869fb…

MALICIOUS

PDF

71.6 KB Created: 2020-12-21 10:48:14 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 681c3fc731775dd612c050414a9d4c48 SHA-1: db764d24be9b87308780e82ceb0c8bc3fa3324ba SHA-256: 7a235c21c3f869fb59c6609788006325fa4e173b484e7c2d76919057655a0597
156 Risk Score

Malware Insights

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

The PDF file contains a large number of external links, many of which point to benign-looking documents. However, one critical heuristic identified a 'PDF_SEO_LINK_FARM' indicating a mass of external links, and another heuristic flagged an external URI pointing to 'trafficel.ru'. The ML classifier and ClamAV detection strongly indicate maliciousness, likely related to phishing or malware distribution through these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • 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
  • 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://trafficel.ru/strik?utm_term=kitten+runts+problems
    • https://cdn-cms.f-static.net/uploads/4389365/normal_5fba896e30956.pdf
    • https://vilaferadir.weebly.com/uploads/1/3/4/7/134771168/7323803.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://s3.amazonaws.com/fikuvine/what_is_a_successor_trustee_of_a_revocable_trust.pdf
    • https://static1.squarespace.com/static/5fc5bd09a5bc066edfc6a90b/t/5fd709c2154d7278710355d6/1607928259538/a_n_m_ka_form_kab_niklega.pdf
    • https://s3.amazonaws.com/jazuravazaguz/javascript_date_format_uk.pdf
    • https://s3.amazonaws.com/fukepez/pezodewuvewomezele.pdf
    • https://s3.amazonaws.com/tawosutosuxi/xakega.pdf
    • https://s3.amazonaws.com/zupenafud/ccna_200-_125_drive.pdf
    • https://s3.amazonaws.com/fusidejebi/concept_of_life_cycle_costing.pdf
    • https://s3.amazonaws.com/tixeligufokup/bulk_insert_format_file_skip_column.pdf
    • https://s3.amazonaws.com/dudurat/falmouth_maine_little_league_baseball.pdf
    • https://static1.squarespace.com/static/5fc4c1dc0b6b03258f4e1bb4/t/5fd670297fc52c2069266b25/1607888937952/doteka.pdf
    • https://s3.amazonaws.com/waxegatulo/7959773858.pdf
    • https://uploads.strikinglycdn.com/files/725e5483-c759-494c-a196-0acce361f2b6/23638186439.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_off0000df66.bin
2a0f22b278474b88b26c44b5192a6b182dbe42b519b2a09244f27ffb6d5a0705
pdf-font-stream PDF embedded font (sfnt) at offset 0xDF66 4864 bytes
font_01_sfnt_off0000efd9.bin
aa50490afde573a30a33e2b2a21b760895e618467da2a6bb438a98b837801035
pdf-font-stream PDF embedded font (sfnt) at offset 0xEFD9 9828 bytes