Malicious PDF — malware analysis report

Static analysis result for SHA-256 541731f98205ed55…

MALICIOUS

PDF

44.9 KB Created: 2020-08-29 02:07:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: ef6eeef255cf0ebdfc24b5e54886083c SHA-1: ed0b9cac5c03c5a1e952d5a1e6ae8c3d66e4aba7 SHA-256: 541731f98205ed556c622680c52b8c91b29e2a1ab46ab731db085a3c44602c6f
152 Risk Score

Malware Insights

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

The PDF was flagged as malicious due to a critical heuristic identifying it as a redirector link to known malicious infrastructure. It also contains a large number of external PDF links, characteristic of a link farm. The primary malicious IOC is the URL 'https://ttraff.com/wix?keyword=printable+kindergarten+reading+fluency+passages', which is likely used to lure victims. The PDF structure itself appears to be generated by wkhtmltopdf, and the document body contains garbled text along with the suspicious 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.com/wix?keyword=printable+kindergarten+reading+fluency+passages
    • https://static.usrfiles.com/ugd/b8c837_1aed5547cec8470bb834ad8deeacf55a.pdf
    • https://static.usrfiles.com/ugd/b8c837_04bc38d6629049f2a9ed1c607aa7d445.pdf
    • https://static.usrfiles.com/ugd/b8c837_fff527f9ecb640cdbec00fae286b41a2.pdf
    • https://static.usrfiles.com/ugd/b8c837_b4a0729e245046edae04b76f9e289909.pdf
    • https://static.usrfiles.com/ugd/b8c837_2ce3bcebea834af9bfb1ef3d55410540.pdf
    • https://static.usrfiles.com/ugd/b8c837_9abab5f4223340ff8e3b20c4ce967fee.pdf
    • https://static.usrfiles.com/ugd/b8c837_f9041e3a4ecf47f2bb1f5f26774a73c0.pdf
    • https://static.usrfiles.com/ugd/b8c837_fd4b319d51fe4425b795c71f3345c35d.pdf
    • https://static.usrfiles.com/ugd/b8c837_052d99a1c8654a9eaa0a961d2708cee3.pdf
    • https://static.usrfiles.com/ugd/b8c837_1868644f22254e8fa3d860ac5f3c841c.pdf
    • https://static.usrfiles.com/ugd/b8c837_db43475c013b4a038cbe994afa5ee37f.pdf
    • https://static.usrfiles.com/ugd/b8c837_6dd67fe05b064a9787b6cc2a7dcf6836.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00005a8d.bin
e3a44aebbad343a9ee65a7795ff0c46374fcd9b8edd6855632153420c36ebe16
pdf-font-stream PDF embedded font (sfnt) at offset 0x5A8D 5632 bytes
font_01_sfnt_off00006dbe.bin
aeb3e9554c99238960ff4b632264025c089fcae935a9cb6c983131cfd24e2382
pdf-font-stream PDF embedded font (sfnt) at offset 0x6DBE 10148 bytes
font_02_sfnt_off000090a4.bin
531e37f64a2e7dc3bfb257675d9e6c644c7b1597f33ba9a969cd005a7ed65660
pdf-font-stream PDF embedded font (sfnt) at offset 0x90A4 16312 bytes