Malicious PDF — malware analysis report

Static analysis result for SHA-256 c1656ea17421016a…

MALICIOUS

PDF

31.9 KB Created: 2020-08-15 09:28:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: d8f3a6778d294a4d1f0d26fb2740d9c8 SHA-1: c8ecdf27ae741590b789a74de513763bd59e3707 SHA-256: c1656ea17421016ae6a4f159c15beb2ba19fd22ebd4068c058481d95bd50ec8f
152 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1059.001 PowerShell T1204.002 Malicious Link

The PDF contains a large number of embedded links, many of which point to domains associated with link farms and redirectors, as indicated by the PDF_SEO_LINK_FARM and PDF_MALICIOUS_REDIRECTOR_LINK heuristics. One critical URL, https://ttraff.ru/wb?keyword=algebra%202%20complex%20numbers%20worksheets%20with%20answers, is flagged as malicious. The document body, though heavily obfuscated, contains references to educational content, suggesting a lure. The ML classifier also strongly indicated 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.ru/wb?keyword=algebra%202%20complex%20numbers%20worksheets%20with%20answers
    • http://xawimixi.cleanclutterfree.com/uploads/1/3/1/8/131871509/negipufivukedizafi.pdf
    • http://sikup.sandavillas.com/uploads/1/3/1/4/131482962/vedawapuram-bujogaxi-risigudamewupo-nikopav.pdf
    • https://cdn.shopify.com/s/files/1/0437/7909/6728/files/10384812507.pdf
    • https://cdn.shopify.com/s/files/1/0435/0902/2886/files/refam.pdf
    • https://cdn.shopify.com/s/files/1/0438/3339/3309/files/wewobipusexage.pdf
    • https://cdn.shopify.com/s/files/1/0433/3341/9166/files/niti_aayog_aspirational_districts.pdf
    • https://cdn.shopify.com/s/files/1/0434/7405/9430/files/wuvifexejimuwete.pdf
    • https://cdn.shopify.com/s/files/1/0432/8580/7269/files/7149065412.pdf
    • https://cdn.shopify.com/s/files/1/0433/0687/7080/files/tevedizulav.pdf
    • https://cdn.shopify.com/s/files/1/0431/6397/5835/files/download_terjemahan_kitab_bidayatul_mujtahid.pdf
    • https://cdn.shopify.com/s/files/1/0437/0549/9803/files/54946655217.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_off000040d8.bin
cb26c11d1f4f16fbac5a938dce628601265ddbc1176642e14114a38441bc1869
pdf-font-stream PDF embedded font (sfnt) at offset 0x40D8 5832 bytes
font_01_sfnt_off0000549a.bin
cea7d03214918c0b3ee5d7242d3d36d71cd990c4825913786d80e43a666b2d59
pdf-font-stream PDF embedded font (sfnt) at offset 0x549A 8836 bytes