Malicious PDF — malware analysis report

Static analysis result for SHA-256 227a7541fa9dee7a…

MALICIOUS

PDF

33.4 KB Created: 2020-09-09 05:41:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: e673c1de5c8ed249e56a6268b348fe28 SHA-1: 2d52783c849a04d149375f990976ee6035b16b08 SHA-256: 227a7541fa9dee7accfb661e77bd1a1633acec7780981f343915f6e114257017
154 Risk Score

Malware Insights

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

The PDF contains a critical heuristic firing for a malicious redirector link, directing users to 'https://ttraff.me/wix?keyword=a+level+chemistry+revision+sheets'. Additionally, it exhibits characteristics of a PDF link farm, embedding numerous external links, including one to 'https://static.usrfiles.com/ugd/cafc24_6e32fc8d3d0e48f58d391d1082be9df4.pdf'. The ML classifier also strongly flagged this PDF as malicious. The document body, though heavily obfuscated, contains the malicious URL and other PDF metadata.

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.me/wix?keyword=a+level+chemistry+revision+sheets
    • https://static.usrfiles.com/ugd/cafc24_6e32fc8d3d0e48f58d391d1082be9df4.pdf
    • https://static.usrfiles.com/ugd/4733ca_31b77da5bc3741288223770e1c0321e8.pdf
    • https://static.usrfiles.com/ugd/5e8de6_47ad001375cd467ea761e62a85d3d474.pdf
    • https://static.usrfiles.com/ugd/04e6f9_cb4aecb750f14b32a51a809ae85a5136.pdf
    • https://static.usrfiles.com/ugd/d79848_e4d55e05577c420a8691069cc3eedd54.pdf
    • https://static.usrfiles.com/ugd/2f7489_bdacbbe33c424bb4a13b5891de3e2f08.pdf
    • https://static.usrfiles.com/ugd/11f207_bbb10946df9a4521b5e40d2b65000336.pdf
    • https://static.usrfiles.com/ugd/3cb679_1640718521274ec985d009d4b87e96b2.pdf
    • https://static.usrfiles.com/ugd/359e64_2e320c95724848588594e70e165df180.pdf
    • https://static.usrfiles.com/ugd/b8c837_b773e220c0374784937e1a949d98038a.pdf
    • https://static.usrfiles.com/ugd/4b7290_a56c718dc05b4b0fba127546066861ca.pdf
    • https://static.usrfiles.com/ugd/df4650_35020e89a2fc42c2a37670c884815722.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_off0000457c.bin
15bc7e0f751061d0d0f87aa23ce71f9af5392de67a8491368481ee6324e900f1
pdf-font-stream PDF embedded font (sfnt) at offset 0x457C 4980 bytes
font_01_sfnt_off0000564f.bin
faa62a8a88d967d2aeedd365a1b5f71b51d6b136eeaeb04250f9d479b1390ef7
pdf-font-stream PDF embedded font (sfnt) at offset 0x564F 10100 bytes