Malicious PDF — malware analysis report

Static analysis result for SHA-256 668101f29cc3daae…

MALICIOUS

PDF

74.9 KB Created: 2021-06-01 09:58:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 506c89cb57a144ea8600af50ad39ace4 SHA-1: d968620f37513136e0d401d83501276ad0dbce5b SHA-256: 668101f29cc3daae3d3bcb755c0f40de868ef51a998e26bf4e2a102be9120d4f
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file contains numerous external links, indicating a link farm or phishing attempt. The heuristic PDF_SEO_LINK_FARM specifically flags the presence of a mass external PDF link farm. ClamAV also detected this file as Pdf.Phishing.Trojan, further supporting its malicious nature. The document body, though heavily obfuscated, suggests a lure related to 'worksheet answers'.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://nomylo.ru/pbw?utm_term=writing+equations+of+parallel+and+perpendicular+lines+worksheet+answers
    • https://bosebekepomij.weebly.com/uploads/1/3/4/8/134870535/liwojimileximevu.pdf
    • https://static.s123-cdn-static.com/uploads/4445871/normal_600868601ffa6.pdf
    • https://dobuxavebixeli.weebly.com/uploads/1/3/4/7/134725246/kerudawujos_vexas_velunox_bodumovenaz.pdf
    • https://cdn-cms.f-static.net/uploads/4484815/normal_604495c59d6d1.pdf
    • https://cdn-cms.f-static.net/uploads/4366381/normal_6064445b3f7bd.pdf
    • https://static.s123-cdn-static.com/uploads/4408713/normal_5feb0ece94132.pdf
    • https://nawawuxilebop.weebly.com/uploads/1/3/4/6/134679594/kegekuxipuxigopa.pdf
    • https://jameropavide.weebly.com/uploads/1/3/4/6/134699307/sigoruja.pdf
    • https://losiweso.weebly.com/uploads/1/3/1/3/131380476/0948246f5bcf.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://uploads.strikinglycdn.com/files/2bb9f798-9dfc-4f18-8401-a6244881c23d/sewibonikebegubab.pdf
    • http://kufavuva.pbworks.com/f/why_did_my_grandfather_clock_stop_chiming.pdf
    • https://uploads.strikinglycdn.com/files/c54687ba-890f-4885-a7e6-39262d78de36/when_you_know_its_wrong_quotes.pdf
    • https://uploads.strikinglycdn.com/files/84902251-0e3a-4bc1-91ec-c8ec5ebc7247/dosusemegikagevon.pdf
    • https://uploads.strikinglycdn.com/files/473ac7fa-52b5-467e-b6a8-6617536a0046/ganudomixax.pdf
    • https://uploads.strikinglycdn.com/files/6e62ff87-8169-48d8-979d-0268a897b007/relaruzegivapuletelilo.pdf
    • https://uploads.strikinglycdn.com/files/63010646-8d45-4538-a65a-83aa8f5ee019/69657704901.pdf
    • https://uploads.strikinglycdn.com/files/a4dc1269-33ff-4356-bde8-9b9b3bc6442d/is_getting_free_robux_illegal.pdf
    • http://didaneguk.pbworks.com/w/file/fetch/144428985/europass_cv_sample.pdf
    • https://uploads.strikinglycdn.com/files/19fa6d87-fb74-49a7-8a35-393fce2a9f32/3024654646.pdf
    • https://uploads.strikinglycdn.com/files/db8b912b-4a1a-42cc-b2c4-5d0d5143b04f/wokuxofazepowujile.pdf
    • https://uploads.strikinglycdn.com/files/19de1c46-aa55-45a1-b901-8ce22aea109c/mateo_is_constructing_an_equilateral_triangle_inscribed_in_a_circle_with_center_p.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_off0000e2a8.bin
4a4194228fff94af46e98393c6b300e45eeb65bea7abc8c61c63ddd4534db74d
pdf-font-stream PDF embedded font (sfnt) at offset 0xE2A8 5712 bytes
font_01_sfnt_off0000f630.bin
06a4e0b8b8c17f39112cb347fb6565968879444ecd735e66b4d38ff7da9a850a
pdf-font-stream PDF embedded font (sfnt) at offset 0xF630 11592 bytes