Malicious PDF — malware analysis report

Static analysis result for SHA-256 87ea67e74f181239…

MALICIOUS

PDF

80.8 KB Created: 2021-03-20 11:15:16 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: bcfff179611aeecebe9cd94a23d6faad SHA-1: ec728978a50790eb2d8b084b47d6467570387cf9 SHA-256: 87ea67e74f1812391f5c08aab5cef00102eeb8b4f750215ea938f2b845961a3f
96 Risk Score

Malware Insights

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

The PDF file contains a large number of external links, characteristic of a link farm designed to improve search engine rankings or distribute traffic. One prominent URL, 'https://nipisod.ru/strik?utm_term=how+do+i+use+safety+1st+thermometer', suggests a lure related to a product search. The ML classifier strongly flagged this PDF as malicious, and the presence of embedded links indicates an attempt to direct users to potentially harmful sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

Heuristics 4

  • 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.
  • 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=how+do+i+use+safety+1st+thermometer
    • https://cdn-cms.f-static.net/uploads/4380411/normal_5fd1b59ea1e0f.pdf
    • https://static.s123-cdn-static.com/uploads/4381964/normal_5fec2099660de.pdf
    • https://cdn-cms.f-static.net/uploads/4499636/normal_603cfef1e599a.pdf
    • https://cdn-cms.f-static.net/uploads/4376621/normal_60473aab0f172.pdf
    • https://static.s123-cdn-static.com/uploads/4374022/normal_5ffa94f53b10a.pdf
    • https://static.s123-cdn-static.com/uploads/4384152/normal_5ff428bd08ddb.pdf
    • https://cdn-cms.f-static.net/uploads/4474231/normal_600c9dde9be84.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://s3.amazonaws.com/fakuguvil/52204594263.pdf
    • https://uploads.strikinglycdn.com/files/2a8dd6d3-5a62-4bbd-92ab-78d76be66115/kidugazidiwa.pdf
    • https://s3.amazonaws.com/dowesitobuga/learn_english_grammar.pdf
    • https://5c54d0bb-9de8-469b-abb1-33232a952ba9.filesusr.com/ugd/370e3f_8ba1ab925ca7408689bf8ed4ec2048cb.pdf?index=true
    • https://uploads.strikinglycdn.com/files/57eed1d7-be91-4a4e-be17-8152587172e3/5270560443.pdf
    • https://uploads.strikinglycdn.com/files/e11b9ec4-791c-4670-9819-3aac8fdf01ba/asus_laptop_q550lf_drivers.pdf
    • https://74a5c9af-61bb-4d76-9351-4d02c0bf652a.filesusr.com/ugd/e33828_5139633d6c144a1aaa306cb7caa0079c.pdf?index=true
    • https://uploads.strikinglycdn.com/files/b74ab9da-98ae-45df-b409-b5a091efaeac/a_memory_of_light_ebook_cover.pdf
    • https://636e06b3-920c-4898-b827-ef778bbbc101.filesusr.com/ugd/40512e_28f7a50ad5554c15916a8303f8bce87d.pdf?index=true
    • https://uploads.strikinglycdn.com/files/a7562ef7-722d-4317-9f6f-b4f00e1fd84a/how_much_do_traffic_cops_get_paid_uk.pdf
    • https://uploads.strikinglycdn.com/files/a57e585f-ee96-45ba-bdf1-5d88e584d214/kingdom_hearts_strategy_guide.pdf
    • https://uploads.strikinglycdn.com/files/0e2c46b6-d3e4-4c02-9847-5463f4c0ff85/onyx_plus_with_home_kit_model__sxpl1h1.pdf
    • https://uploads.strikinglycdn.com/files/50e26755-9b86-4dcf-84b9-14c386232fee/fakubugoguzip.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f337.bin
fae8839a7619de21587d5c93ad073155f08e9f425cb8e5648cc6bd95ec423cda
pdf-font-stream PDF embedded font (sfnt) at offset 0xF337 5324 bytes
font_01_sfnt_off0001053a.bin
60647be669732315999495f41d25bbccfa8721db7fcd94573166c2f0792152c2
pdf-font-stream PDF embedded font (sfnt) at offset 0x1053A 2712 bytes
font_02_sfnt_off000110d6.bin
0219edbf71371b679b634f70e52b6907f3a93f4b8f324a05e752e19618f790eb
pdf-font-stream PDF embedded font (sfnt) at offset 0x110D6 10776 bytes