Malicious PDF — malware analysis report

Static analysis result for SHA-256 7cfaabbd0f7c2064…

MALICIOUS

PDF

42.6 KB Created: 2020-08-31 21:56:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: c8e9af46397c7e6d61a18cbb86ea3f26 SHA-1: f20c5a0f133251c9d7345233e1314d7f099186ac SHA-256: 7cfaabbd0f7c20649c63233549c87074d2e1fa2021900066c08951b6b96cc993
154 Risk Score

Malware Insights

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

The PDF contains embedded links, one of which, 'https://ttraff.cc/wix?keyword=assistant+teacher+interview+questions+and+answers+pdf', is flagged as a malicious redirector. The document body, though heavily obfuscated, appears to contain text related to interview questions, suggesting a lure. The presence of numerous other PDF links, many pointing to 'usrfiles.com', indicates a link farm strategy, likely to obscure the malicious redirector. The ML classifier strongly indicates 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=assistant+teacher+interview+questions+and+answers+pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • https://static.usrfiles.com/ugd/dc98cc_b283d94432cc424a9f51e2dbb25d1590.pdf
    • https://static.usrfiles.com/ugd/b8c837_4d0dcc6942254291ad08b1dd63b43c85.pdf
    • https://static.usrfiles.com/ugd/b8c837_3af5d69f79524033a29d31b85a9af94a.pdf
    • https://static.usrfiles.com/ugd/d17951_9becdaffeee6491ca6ab58217c12f90b.pdf
    • https://cdn.shopify.com/s/files/1/0450/5042/9598/files/cbc_blood_test_normal_values_chart.pdf
    • https://cdn.shopify.com/s/files/1/0428/4756/8039/files/56127960505.pdf
    • https://cdn.shopify.com/s/files/1/0437/8476/5602/files/2020_april_current_affairs_in_tamil.pdf
    • https://static.usrfiles.com/ugd/b8c837_b458b3bc71f041ed8de160528ca3fe6f.pdf
    • https://static.usrfiles.com/ugd/0a593f_35c961677f4c40848d368c54ef2ca5e2.pdf
    • https://static.usrfiles.com/ugd/b8c837_dbfb65b7e1a24f628eca6b1112a25e08.pdf
    • https://cdn.shopify.com/s/files/1/0440/7810/4728/files/gajetifexuruseri.pdf
    • https://cdn.shopify.com/s/files/1/0434/6635/8934/files/french_adverbs_exercises.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_off0000682a.bin
914acb5d34258742a5e12e52d9678b483d7b630e752f323a1a640156594fff78
pdf-font-stream PDF embedded font (sfnt) at offset 0x682A 5476 bytes
font_01_sfnt_off00007adb.bin
b6b658aadcb889bdbbc5f12e4d0a43997ef7803e93235ebac90bc4b6475094c4
pdf-font-stream PDF embedded font (sfnt) at offset 0x7ADB 10416 bytes