Malicious PDF — malware analysis report

Static analysis result for SHA-256 6a618c62c0350928…

MALICIOUS

PDF

97.3 KB Created: 2021-05-18 03:45:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-09-13
MD5: 502a8f46a5f14084e22682e7b38035c0 SHA-1: 57f0de9e52bb644c60b9d1e0364533ac397abc29 SHA-256: 6a618c62c0350928ffd5481490f449fbc22dd66eb3c548d4ee122c9ce2e00d39
196 Risk Score

Malware Insights

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

The PDF contains numerous external links, many pointing to SEO-optimized PDF files, suggesting a link farm or redirector strategy. The primary URL, https://nipisod.ru/strik?utm_term=circle+word+problems+worksheet+answers, is flagged as a redirector and associated with phishing lures. ClamAV and ML classifiers also identified this PDF as malicious, likely due to its link-farming and redirection behavior.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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.
  • 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.
  • 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://nipisod.ru/strik?utm_term=circle+word+problems+worksheet+answers PDF link annotation
    • http://dunatizikasinab.22web.org/mastoidite_traitement.pdfIn PDF document text
    • http://sobanurosu.22web.org/7491397007.pdfIn PDF document text
    • https://zaxixeresez.weebly.com/uploads/1/3/1/8/131871416/9149910.pdfIn PDF document text
    • https://dedemapisiwopiv.weebly.com/uploads/1/3/0/7/130775251/d6f6dc.pdfIn PDF document text
    • https://koxofekidoponu.weebly.com/uploads/1/3/3/9/133997415/1615933.pdfIn PDF document text
    • http://kotexob.iblogger.org/take_off_past_tense_form.pdfIn PDF document text
    • https://deremufirig.weebly.com/uploads/1/3/4/8/134854029/4124100.pdfIn PDF document text
    • https://detopeda.weebly.com/uploads/1/3/4/3/134305225/4731506e1.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/webipejonavuv/how_to_write_for_seo_2020.pdfIn PDF document text
    • http://pabenikazugaj.rf.gd/wagner_flexio_590_paint_sprayer_review.pdfIn PDF document text
    • https://s3.amazonaws.com/resabomibogodaw/nikimitepawiduma.pdfIn PDF document text
    • https://s3.amazonaws.com/jazamerijekufol/95171530418.pdfIn PDF document text
    • http://gavofuduwaxene.epizy.com/72593558639.pdfIn PDF document text
    • http://kujujigufa.epizy.com/20508529131.pdfIn PDF document text
    • https://s3.amazonaws.com/zidosozawok/android_x86_linux.pdfIn PDF document text
    • https://s3.amazonaws.com/dowadotiju/tratados_comerciales_de_mexico.pdfIn PDF document text
    • http://pevixogojo.epizy.com/fetoxofagodifizowu.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000137cf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x137CF 2828 bytes
SHA-256: b7f317aa0f29cd34df008dc84d8f376d2685882a57a4a5cd0d86477d0adf885a
font_01_sfnt_off000141ca.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x141CA 5512 bytes
SHA-256: 4bb3a787f69df89a89dd8a9cf59db505383bfc00d2782690c7c027120455e81e
font_02_sfnt_off0001545f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1545F 10352 bytes
SHA-256: 3091813e53edc3d0096fab1441cb836814144c7d606ebe40cee454e935914b44

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