Malicious PDF — malware analysis report

Static analysis result for SHA-256 87b77bcd21d16fd2…

MALICIOUS

PDF

38.7 KB Created: 2020-08-29 22:00:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: f4929173c6ecdc96f666bdd45eb74e27 SHA-1: 17594572ca8a6de99851221abab2a9484da2a635 SHA-256: 87b77bcd21d16fd2abad329accabc182ef120f13800c6423a647478d1fe58793
154 Risk Score

Malware Insights

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

The PDF contains embedded links, with one identified as a malicious redirector and others forming a link farm. The ML classifier also flagged this PDF as malicious. The document body, though heavily obfuscated, contains text related to 'Ielts writing task 1 map structure' and a URL that aligns with the malicious redirector finding, suggesting a lure for users interested in such topics. The presence of numerous embedded links points towards an attempt to drive traffic to potentially harmful sites.

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=ielts+writing+task+1+map+structure
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://static.usrfiles.com/ugd/b8c837_3849cf880a9d411e869eb4303ccdca74.pdf
    • https://static.usrfiles.com/ugd/b8c837_a4a4401df53745c78a80f00dd8fe5a83.pdf
    • https://static.usrfiles.com/ugd/b8c837_9eace22d32914984a2f7a99007a56742.pdf
    • https://static.usrfiles.com/ugd/b8c837_8df052a8eff54f639f43a71e5b786c04.pdf
    • https://static.usrfiles.com/ugd/b8c837_5e7c9c0c6b8a4e9dac1d6d36128f7545.pdf
    • https://static.usrfiles.com/ugd/a59130_5324d1f918a94c97b8a3599783ccb9ba.pdf
    • https://static.usrfiles.com/ugd/b8c837_4b90efcf3d364fdf8a2a72e895831b98.pdf
    • https://cdn.shopify.com/s/files/1/0464/0545/1931/files/sudotuzis.pdf
    • https://cdn.shopify.com/s/files/1/0432/8685/5840/files/2018_chevrolet_impala_user_manual.pdf
    • https://static.usrfiles.com/ugd/accd1f_b3a0bc6e15df4ecf8cfcf1cce3250af2.pdf
    • https://static.usrfiles.com/ugd/0dcf4b_738d7c09b23f49d09b62820827a5de49.pdf
    • https://static.usrfiles.com/ugd/b8c837_14123bb2b7df4f5b8bded97bc6a65de2.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_off000059e6.bin
e36a98bb4254c426f3e088b70dc9cba0156cd0ec41d901a7b182447d91b0eef8
pdf-font-stream PDF embedded font (sfnt) at offset 0x59E6 5396 bytes
font_01_sfnt_off00006c3f.bin
b630fd4389f5aab79305b39bc7ce8dd71cd48d8a7bad94b5e1676965878306ca
pdf-font-stream PDF embedded font (sfnt) at offset 0x6C3F 9888 bytes