Malicious PDF — malware analysis report

Static analysis result for SHA-256 273518087c84f425…

MALICIOUS

PDF

36.6 KB Created: 2020-08-30 11:47:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 1a435af3f19233460b3267615363cfdd SHA-1: 99c98c945c8969773508434b06d60b6eecb85243 SHA-256: 273518087c84f4255fc5e7bac5a607c9fd593cc7cfab6d3921892399df57d6c3
152 Risk Score

Malware Insights

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

The PDF file contains a significant number of embedded links, with a critical heuristic firing indicating a link to known malicious redirector infrastructure. The document body, though heavily obfuscated, contains URLs that are part of this link farm. The ML classifier also strongly indicated maliciousness. The primary attack pattern appears to be SEO poisoning or a phishing lure through a large number of external links.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 4

  • 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.
  • 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://ttraff.ru/wix?keyword=next+century+mathematics+precalculus+pdf
    • https://static.usrfiles.com/ugd/b8c837_ac9312f5205b4856a04b1b900453e37e.pdf
    • https://static.usrfiles.com/ugd/0f5b72_361932654f074148853ca0b7cc3c7501.pdf
    • https://static.usrfiles.com/ugd/b8c837_dfe740756e4745bbb9da2d2cc664978e.pdf
    • https://static.usrfiles.com/ugd/b8c837_377e04835461445e8a40b43b3bc5259b.pdf
    • https://static.usrfiles.com/ugd/c836c3_86f8f10b4c8843fa9a0418aba403c9b2.pdf
    • https://static.usrfiles.com/ugd/b8c837_a8f2906ae8a04caa8d393c15974df4cc.pdf
    • https://static.usrfiles.com/ugd/b8c837_c90be221867b471ab1ce3eec6149f1c0.pdf
    • https://static.usrfiles.com/ugd/5bb01c_9c664846f2034dff9c4dc5fdd988c912.pdf
    • https://static.usrfiles.com/ugd/e32576_ecbb3a16473140b098e966575f498e31.pdf
    • https://static.usrfiles.com/ugd/b8c837_92d2526c93cb496e9193eaea4a828be4.pdf
    • https://cdn.shopify.com/s/files/1/0436/2610/2947/files/new_rap_albums_2019.pdf
    • https://cdn.shopify.com/s/files/1/0431/7347/8560/files/6185897966.pdf
    • https://static.usrfiles.com/ugd/822ecd_afdc4e887f01469492f61e474ff41c1c.pdf
    • https://static.usrfiles.com/ugd/8e1900_c5cba3ae5d9f483cbab7ebed8f6ebd79.pdf
    • https://static.usrfiles.com/ugd/daca0d_71c8b8a180e8425e8542cdaa6d135621.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/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000050d0.bin
34f1c4433e96c54ed066b932def368a5d666c2af6c4354595e55f579828e1016
pdf-font-stream PDF embedded font (sfnt) at offset 0x50D0 5536 bytes
font_01_sfnt_off00006380.bin
c2be16878d653a7f73c786cbc24ba9df646db696b2e48db138d3f141f57d80e4
pdf-font-stream PDF embedded font (sfnt) at offset 0x6380 9888 bytes