Malicious PDF — malware analysis report

Static analysis result for SHA-256 3998f037a23f9f4b…

MALICIOUS

PDF

42.8 KB Created: 2020-08-31 19:54:19 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 185a2ba6969f93992bf63c0d02ce0159 SHA-1: d4d4390d55a98908ef84f6bc3f7b96911d3c1727 SHA-256: 3998f037a23f9f4b6acb7d33309f2bbd83e9566963b79f3ee0f29e78a8ded726
152 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1059.001 PowerShell

The PDF file was flagged as malicious by a machine learning classifier and contains a significant number of external links, characteristic of a link farm. One of the primary links, 'https://ttraff.ru/pify?keyword=wordbrain+2+word+savant+literature+answers', points to known malicious redirector infrastructure. The document body, though heavily obfuscated, contains references to the malicious URL and appears to be generated by wkhtmltopdf, a tool sometimes used to create malicious PDFs. The presence of a link farm suggests an attempt to obscure the final malicious destination and potentially engage in SEO poisoning or phishing.

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/pify?keyword=wordbrain+2+word+savant+literature+answers
    • https://static.usrfiles.com/ugd/b8c837_b4e5ea3fad004ec3a29dbe9c4c9eb0f7.pdf
    • https://static.usrfiles.com/ugd/b8c837_d78006bb28264b5698053f9d80368bbf.pdf
    • https://static.usrfiles.com/ugd/b8c837_008fd272bb57404784e4a5b0f62817a9.pdf
    • https://static.usrfiles.com/ugd/defcb2_6a95a975bd1943e9a010748b32ccd570.pdf
    • https://cdn.shopify.com/s/files/1/0446/5885/1993/files/free_printable_auto_repair_invoice.pdf
    • https://cdn.shopify.com/s/files/1/0429/1405/4300/files/nuvudid.pdf
    • https://cdn.shopify.com/s/files/1/0435/8258/7039/files/cdc_flu_vaccine_2019.pdf
    • https://cdn.shopify.com/s/files/1/0432/7315/8806/files/warinawaxupej.pdf
    • https://static.usrfiles.com/ugd/b8c837_d2a53d74d6314b2a846eda4372a4e479.pdf
    • https://static.usrfiles.com/ugd/18f527_2c548f84c1a8430ca1fc5480aaee4b2b.pdf
    • https://static.usrfiles.com/ugd/b8c837_d3659f6c8af5494d98e1f132c61d95db.pdf
    • https://static.usrfiles.com/ugd/b8c837_ca34c982b63b496895c4e463bcb72fb7.pdf
    • https://static.usrfiles.com/ugd/7603ae_2736f6c01e564d38baa7faa5351e3024.pdf
    • https://static.usrfiles.com/ugd/57c819_d014d85e315e42888c759d72efbc591a.pdf
    • https://static.usrfiles.com/ugd/b8c837_3020d7d9c3fa4affaa29f456dc8a2463.pdf
    • https://static.usrfiles.com/ugd/b8c837_8a102dd05cd640c09c166b36a8101432.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00005495.bin
3d9eb9e74489dccfa0f6f65e7ccedc69e4f3c436d3f7d60b39eb7bef68277007		 pdf-font-stream PDF embedded font (sfnt) at offset 0x5495 5140 bytes
font_01_sfnt_off00006639.bin
0a896dd70491f45bbcdb97a3aaec30de29ec5ce616437561461898ccf8873c20		 pdf-font-stream PDF embedded font (sfnt) at offset 0x6639 13200 bytes
font_02_sfnt_off00008fd2.bin
1062cd8ddf90f4344fa193b395386d5669df1a952e5759311ca261a71931f361		 pdf-font-stream PDF embedded font (sfnt) at offset 0x8FD2 4324 bytes

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