Malicious PDF — malware analysis report

Static analysis result for SHA-256 5c1cb10a9a5abfa6…

MALICIOUS

PDF

44.0 KB Created: 2020-08-29 12:20:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: e66f762fbc0dbbe18af6377f8dc79309 SHA-1: 2a5e82bc2d60a0bc344e9c8e33ae3bb7bc0cfbfb SHA-256: 5c1cb10a9a5abfa689af6b05d65660147173e9eb75a02c2dd03013371afa45ef
162 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The PDF contains embedded links, one of which points to known malicious redirector infrastructure. The document body, though heavily obfuscated, contains text suggesting it is an 'answer key' and includes the malicious URL. The presence of numerous external PDF links, many of which are benign, suggests a link farm tactic to obscure the malicious redirector. The ML classifier also strongly flagged this PDF as malicious.

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.com/wix?keyword=answer+key+ctet+2019+set+w
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://static.usrfiles.com/ugd/b8c837_bf171a5ef2d744f5b6df74b9ed201237.pdf
    • https://static.usrfiles.com/ugd/b8c837_ec3d7d3d8dd841bf9a75cbc7e12bbe3b.pdf
    • https://static.usrfiles.com/ugd/b8c837_657f591d17b945b486d7ac5fd71ae535.pdf
    • https://static.usrfiles.com/ugd/b8c837_ba8a1ac2bf444e3cbfaadd51892c3988.pdf
    • https://static.usrfiles.com/ugd/b8c837_48236be519ec4488b87f6924a41652a2.pdf
    • https://static.usrfiles.com/ugd/b8c837_e6d1a1a281cd4e11a0b0ea853dca1c83.pdf
    • https://static.usrfiles.com/ugd/b8c837_59ebf0406e384b1493323d529e7fdad0.pdf
    • https://static.usrfiles.com/ugd/b8c837_0250e583e02144f7924434c2d26d83b8.pdf
    • https://static.usrfiles.com/ugd/d78803_005ba72b9bff4a3f9e6c793370d5842b.pdf
    • https://static.usrfiles.com/ugd/b8c837_654768dc757848ccb55b075d94197deb.pdf
    • https://static.usrfiles.com/ugd/b8c837_dce6b614c31746b3a4c9b72b73c21fbc.pdf
    • https://cdn.shopify.com/s/files/1/0438/3604/7525/files/2462418175.pdf
    • https://cdn.shopify.com/s/files/1/0434/2359/6693/files/hager_2928_electric_strike_template.pdf
    • https://cdn.shopify.com/s/files/1/0428/5893/8531/files/65291230260.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_off00006c9f.bin
ee139c9665625f382bacae4d9a8345f6d5c1ae3fc3e6cbc572974cf5072fdc8c		 pdf-font-stream PDF embedded font (sfnt) at offset 0x6C9F 5280 bytes
font_01_sfnt_off00007ec3.bin
647ba0483cd83b31529c92c7d5f8549d9c6e96516268c46c9af359e2222a6110		 pdf-font-stream PDF embedded font (sfnt) at offset 0x7EC3 10824 bytes

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