Malicious PDF — malware analysis report

Static analysis result for SHA-256 f9181e53b4bf93e8…

MALICIOUS

PDF

34.5 KB Created: 2020-08-31 11:48:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: e83c9de0499349db6de11f0460344ec0 SHA-1: 220aee43a32fde32b39d3b37b806639599cf2589 SHA-256: f9181e53b4bf93e8d3842f0ea8c67d7295a6be30f510538c6cff2eb2276c0f45
154 Risk Score

Malware Insights

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

The PDF document was flagged by multiple critical heuristics for containing malicious redirector links and a link farm. The ML classifier also strongly indicated maliciousness. The primary malicious IOC is the URL 'https://ttraff.ru/wix?keyword=stay+piano+chords+sheet+music', which is part of a redirector infrastructure. The document body is heavily obfuscated and appears to contain junk data, but the presence of multiple links to external PDFs suggests a link farm or SEO poisoning attempt to lure users to malicious content.

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=stay+piano+chords+sheet+music
    • https://static.usrfiles.com/ugd/b8c837_42f546c2cd7845dba95f46381acebb02.pdf
    • https://static.usrfiles.com/ugd/b8c837_dd536a2a81474067928e9b4219d4662d.pdf
    • https://static.usrfiles.com/ugd/b8c837_a5ee06e698d144a9bf690d5043493013.pdf
    • https://static.usrfiles.com/ugd/ce14f3_c46f466cc743423097dbf23b50005a10.pdf
    • https://static.usrfiles.com/ugd/b8c837_727865dd33a7465a8431009af0051858.pdf
    • https://static.usrfiles.com/ugd/b8c837_2dfc249b14ab4e81a7130869703d6bdf.pdf
    • https://static.usrfiles.com/ugd/60933b_49c7fa51ef7241649c17fa1ec6d7c7e9.pdf
    • https://static.usrfiles.com/ugd/097bd5_9ddf17d4e03a4de29d8b061f5d0542b6.pdf
    • https://static.usrfiles.com/ugd/52b593_ba927f7e1990409bbb6472ceac776c8e.pdf
    • https://static.usrfiles.com/ugd/b0b521_cfcf340a66024830aa6adb51aa78a940.pdf
    • https://static.usrfiles.com/ugd/b8c837_8f3c9b208a314ac3b35194506fae5083.pdf
    • https://static.usrfiles.com/ugd/b8c837_e2ee54eb1d86408fad4036e2234cd14b.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_off000048a4.bin
71b3ba551a69cae5c457579ac0b346319a4d608ca3d513e916f20683666fd2b3
pdf-font-stream PDF embedded font (sfnt) at offset 0x48A4 5484 bytes
font_01_sfnt_off00005b15.bin
00deba307c922711c04f938e2d5534b3b5c29d06302ae10f20abd8978b923565
pdf-font-stream PDF embedded font (sfnt) at offset 0x5B15 10112 bytes