Malicious PDF — malware analysis report

Static analysis result for SHA-256 a7ac4d6af3fbcd03…

MALICIOUS

PDF

47.1 KB Created: 2020-08-29 03:21:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: dbdd3a59c01c3d824945dfc15f345c1e SHA-1: f9451dc74988ff642dd26ca34fb21268cc28a7f5 SHA-256: a7ac4d6af3fbcd03f5bf0f46ec9aa88a5c3ebddb7fa7bd2533640c5690eb9add
154 Risk Score

Malware Insights

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

The PDF contains a large number of embedded links, with the primary URL pointing to a known malicious redirector. The document body, though heavily obfuscated, contains the same malicious URL and references to other PDFs hosted on static.usrfiles.com, suggesting a link farm or SEO poisoning attempt. The ML classifier also strongly indicated maliciousness.

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.cc/wix?keyword=cool+clan+tag+names+for+black+ops+2
    • https://static.usrfiles.com/ugd/b8c837_bae4ba93a76d481080e3093064abed61.pdf
    • https://static.usrfiles.com/ugd/b8c837_a96b52027037426995c4055e1696a306.pdf
    • https://static.usrfiles.com/ugd/b8c837_8b9369de28884babb502e35e5b2e1cb9.pdf
    • https://static.usrfiles.com/ugd/b8c837_179928909eac40b2b6fdd4043b1e727b.pdf
    • https://static.usrfiles.com/ugd/b8c837_f4aaed9214814f42bbb342f784210ddc.pdf
    • https://static.usrfiles.com/ugd/b8c837_1aa74e5bf9224ce1a1cdd43ee4078785.pdf
    • https://static.usrfiles.com/ugd/b8c837_9189c0d0b57d498f90bb808ddc05231a.pdf
    • https://static.usrfiles.com/ugd/b8c837_3e23a41186604fdda221f1467e8a191e.pdf
    • https://static.usrfiles.com/ugd/b8c837_d3902005ac65449fa4739ab3008de5bf.pdf
    • https://static.usrfiles.com/ugd/b8c837_3a21550afb224f0e8007d37ec4b9f7d6.pdf
    • https://static.usrfiles.com/ugd/b8c837_01dff94f677c43b0b26f763c251e3641.pdf
    • https://static.usrfiles.com/ugd/b8c837_df7deea3c11b460f83a3eadf210e7071.pdf
    • https://static.usrfiles.com/ugd/b8c837_e1973744e4844790b9d1f559f1a097b0.pdf
    • https://static.usrfiles.com/ugd/b8c837_be241b25173547148b0686a4914d5bcf.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_off00006a60.bin
374a97b7c621200f5b000443a58dd4382e103ed16b718ac1e02370be208e6b85
pdf-font-stream PDF embedded font (sfnt) at offset 0x6A60 5432 bytes
font_01_sfnt_off00007cbe.bin
be7acaa7ae1aa183bb04a3b8b9cb44688ecb5446392645fad1b80e69a044bdc4
pdf-font-stream PDF embedded font (sfnt) at offset 0x7CBE 10756 bytes
font_02_sfnt_off0000a181.bin
a542ec26cea93e049a2e27cd59b1347dd9bbdea13775fd7b822b3c2b3136116f
pdf-font-stream PDF embedded font (sfnt) at offset 0xA181 4324 bytes