Malicious PDF — malware analysis report

Static analysis result for SHA-256 4da8b9f7ad499fa7…

MALICIOUS

PDF

37.1 KB Created: 2020-09-01 01:22:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: e5697a76efc2b5627a5ec3c5633204a4 SHA-1: 6da559c2c3b8ed7dbb58fb15f543230d5ce0e819 SHA-256: 4da8b9f7ad499fa7803a5ac7322482d98671e25c0d9f08f79bd95bfe81443d9d
154 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1059.001 PowerShell

The PDF contains embedded links that point to a known malicious redirector, ttraff.ru, which is disguised with a search query for 'toefl junior practice test pdf'. The ML classifier strongly indicated maliciousness, and the PDF structure itself contains a large number of external links, suggesting a link farm or redirection tactic. No scripts were extracted, but the primary malicious behavior is the redirection to the malicious URL.

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=toefl+junior+practice+test+pdf
    • https://static.usrfiles.com/ugd/b8c837_685bba00e4ab4db9b3a08a512e85b923.pdf
    • https://static.usrfiles.com/ugd/5438e3_c9f6bb4d74ee4932b467d341b1dd10f4.pdf
    • https://static.usrfiles.com/ugd/9b5f63_fe92ce3f323a4db2becdcf9b154cfcd9.pdf
    • https://static.usrfiles.com/ugd/b444d4_5115c76bfebd4018b731c5f103f9eeca.pdf
    • https://static.usrfiles.com/ugd/b8c837_c762cac771034d9f9681d8e751bb0e0c.pdf
    • https://static.usrfiles.com/ugd/269bb8_6f53de3cab86454ba8f102de43d29e52.pdf
    • https://static.usrfiles.com/ugd/b8c837_d022d14d9856478c8843aa2368136461.pdf
    • https://static.usrfiles.com/ugd/3be3a7_bade3001604b44868363b5d6f8da255d.pdf
    • https://static.usrfiles.com/ugd/565485_10fee8fbf364414c9a730466a28b1bcd.pdf
    • https://static.usrfiles.com/ugd/b8c837_1419d63d92f34f3ca6cab4cd2a702b00.pdf
    • https://static.usrfiles.com/ugd/d78803_e988b393dcdd4935aafbf1ce961d2944.pdf
    • https://static.usrfiles.com/ugd/b8c837_652ec82e4edf4d4abc86e2035eafe8e9.pdf
    • https://cdn.shopify.com/s/files/1/0430/3912/9751/files/edit_free_mac_os_x.pdf
    • https://cdn.shopify.com/s/files/1/0432/4212/7527/files/76389516455.pdf
    • https://cdn.shopify.com/s/files/1/0433/4639/5304/files/86353897740.pdf
    • https://cdn.shopify.com/s/files/1/0432/9983/1968/files/zixemiposejigub.pdf
    • https://cdn.shopify.com/s/files/1/0434/4581/3414/files/wutokamajirobolofupul.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_off000053dc.bin
5bed737a3fbd7e8111969f31c59833f97db0b2545c176f4d1c658d304403addf
pdf-font-stream PDF embedded font (sfnt) at offset 0x53DC 5172 bytes
font_01_sfnt_off00006587.bin
f3e11c7dc8badfc0f85897af288590c2fb22730522f257457b51fb008dbab827
pdf-font-stream PDF embedded font (sfnt) at offset 0x6587 9976 bytes