Malicious PDF — malware analysis report

Static analysis result for SHA-256 ac883dedb8949641…

MALICIOUS

PDF

34.3 KB Created: 2020-09-02 20:20:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: c94809bca8b704e9bda4074aa25e5be2 SHA-1: 0cdb6558d7ad9fc3f87e4a16e955fba9c2eb21b9 SHA-256: ac883dedb894964167aa6ad4d5a3633b3c75c3321926df45adfcb4bc21819252
152 Risk Score

Malware Insights

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

The PDF contains a link to a known malicious redirector, ttraff.ru, which is disguised as a 'declarative and interrogative sentences worksheet 3rd grade'. This indicates a social engineering attempt to trick the user into visiting a malicious site. The ML classifier also strongly flagged this PDF as malicious. The presence of numerous links to external PDFs, many hosted on static.usrfiles.com, suggests a link farm or SEO poisoning tactic to improve search engine ranking for malicious content.

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=declarative+and+interrogative+sentences+worksheet+3rd+grade
    • https://static.usrfiles.com/ugd/b8c837_dd3e25d7631a44d99af8c9a5ed94781c.pdf
    • https://static.usrfiles.com/ugd/7c30af_665a41b5ad3347fb826fe2b9f0f0986a.pdf
    • https://static.usrfiles.com/ugd/fd3290_0e2f59fdb70f4d2e880916695f4ee63e.pdf
    • https://static.usrfiles.com/ugd/e4a001_c9faa0bfbd2a48cbb46473bed3b8f377.pdf
    • https://static.usrfiles.com/ugd/0a593f_78ceee5b45b1496f9cfe5d3b5ac9396e.pdf
    • https://static.usrfiles.com/ugd/384ea4_9b08b1b67e6a473999e9580e810d4dbb.pdf
    • https://static.usrfiles.com/ugd/b8c837_331ad7e87edc4c14a3869fe8a9245b56.pdf
    • https://cdn.shopify.com/s/files/1/0431/6410/6908/files/gewagugijafovugofe.pdf
    • https://cdn.shopify.com/s/files/1/0429/6222/3263/files/candy_crush_online_games_free.pdf
    • https://cdn.shopify.com/s/files/1/0429/3158/5180/files/dijupep.pdf
    • https://cdn.shopify.com/s/files/1/0430/2562/9335/files/case_study_research_pdf_example.pdf
    • https://cdn.shopify.com/s/files/1/0440/8636/2264/files/aramco_operational_calendar_2019.pdf
    • https://static.usrfiles.com/ugd/b6aaa0_ac4c19d4bad548578e57f6847227b728.pdf
    • https://static.usrfiles.com/ugd/f967ac_a3ce852bc4fa4b8a99d9443b573ae695.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_off00004650.bin
97d9ac4ccfcee09eab876b1d54b97d578ac462ad0e49c5a39c215450c5224aa0
pdf-font-stream PDF embedded font (sfnt) at offset 0x4650 5580 bytes
font_01_sfnt_off00005966.bin
85a4bf4349a14099769d70e334c56ece1b32fa7091d51b0744f9692122952cf3
pdf-font-stream PDF embedded font (sfnt) at offset 0x5966 10252 bytes