Malicious PDF — malware analysis report

Static analysis result for SHA-256 63f8efdd9719a676…

MALICIOUS

PDF

59.6 KB Created: 2020-08-29 18:58:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 1e94568aad1d5a36fa4bf9032c31dd5c SHA-1: 5b88cf223866073147b035ee6f4ce3b657b2b5d5 SHA-256: 63f8efdd9719a676277f8a3a8bbe41b5a029d8e10eb8dc21b843ba3b09d739a9
162 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains a critical heuristic firing for linking to known malicious redirector infrastructure. Additionally, it exhibits characteristics of a PDF link farm, with numerous external links, one of which is identified as a potential download lure. The ML classifier strongly supports the malicious nature of this PDF. The primary IOC is the redirector URL, which is likely used to serve a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 5

  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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=miller+and+levine+biology+textbook+t
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://static.usrfiles.com/ugd/b8c837_6821137c406144e4a16a979c4c63d974.pdf
    • https://static.usrfiles.com/ugd/b8c837_3635a1af29d649b2bb88033299c6ccbd.pdf
    • https://static.usrfiles.com/ugd/136d07_c315c4802bcb4724992fbcdee5164e80.pdf
    • https://static.usrfiles.com/ugd/cfa91a_8d6c272c7d7b4e268d17f301775f0370.pdf
    • https://static.usrfiles.com/ugd/b8c837_6b04013cab2f47e3a52409404ed29aea.pdf
    • https://static.usrfiles.com/ugd/b8c837_3bf0aa6a44964d9e9b467b3dd839b70e.pdf
    • https://static.usrfiles.com/ugd/dd4472_a50acb4f47c74e23b82f7c3e4acdb1eb.pdf
    • https://static.usrfiles.com/ugd/b8c837_0252aac7b25f41178d4ae09497bf6393.pdf
    • https://static.usrfiles.com/ugd/b8c837_b321b21320a64d7cbcbbbf065576e80b.pdf
    • https://static.usrfiles.com/ugd/b8c837_0a560332b1db4a369b903a7325c4cee6.pdf
    • https://static.usrfiles.com/ugd/b8c837_7f354766dc8c496ab16c26d508c0557a.pdf
    • https://static.usrfiles.com/ugd/de65f7_3ddc0629801d47208ff208d99413ca0f.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_off0000aa4d.bin
c10c14783884132e94e525d3060f8c0b738ac62ce465cebbc6e5ee8c792ead48
pdf-font-stream PDF embedded font (sfnt) at offset 0xAA4D 5256 bytes
font_01_sfnt_off0000bc47.bin
603ccfaf49a895c5b67ccd13d8e3fde39bb392795d9d7bb53fad74be1e4476b5
pdf-font-stream PDF embedded font (sfnt) at offset 0xBC47 10872 bytes