Malicious PDF — malware analysis report

Static analysis result for SHA-256 4e8ee5e41b91b851…

MALICIOUS

PDF

37.9 KB Created: 2020-08-31 08:22:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: cd0244c6bf5a3012c802df345e3d0e5a SHA-1: fcf2ba94873ab74af1795183eaafe9a8e7b925ce SHA-256: 4e8ee5e41b91b851b213b4e106efbf4d50e6766fef8ea8e564551a76bf38976c
152 Risk Score

Malware Insights

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

The PDF contains a heuristic firing for a malicious redirector link, specifically pointing to 'https://ttraff.cc/wix?keyword=examen+matematicas+1+bachillerato+ci'. The document body, though heavily obfuscated, also contains this URL and numerous other links to static.usrfiles.com, suggesting a link farm or redirection strategy. The ML classifier also strongly flagged this PDF as malicious. The primary attack pattern involves luring the user to a malicious site via a link embedded within the document.

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=examen+matematicas+1+bachillerato+ci
    • https://static.usrfiles.com/ugd/b8c837_78dc4acaef3a41d4bac33137316ff669.pdf
    • https://static.usrfiles.com/ugd/857e61_817c9ba1047948d5b3904ce46127f88a.pdf
    • https://static.usrfiles.com/ugd/9c43ec_7ea98b230f584e4882327402ab5e988b.pdf
    • https://static.usrfiles.com/ugd/12f4eb_09b3da9683da43c5b077014515bbf9a9.pdf
    • https://static.usrfiles.com/ugd/b8c837_90b82dd3c4f5440cb9f5d1adc5df0bd1.pdf
    • https://static.usrfiles.com/ugd/822ecd_31d7a61586964f31bf761d1169c6d163.pdf
    • https://static.usrfiles.com/ugd/df4650_0abf960924304a91b23c984e80abc47e.pdf
    • https://static.usrfiles.com/ugd/e2c6c1_58518293b92049f8b8f923cbf6e79308.pdf
    • https://static.usrfiles.com/ugd/493135_3c83c9215ca649aea4437287cb4b60e7.pdf
    • https://static.usrfiles.com/ugd/c7ef1a_bc5c12fe5066407ebd3aac74012de626.pdf
    • https://cdn.shopify.com/s/files/1/0431/8075/3058/files/5341357801.pdf
    • https://cdn.shopify.com/s/files/1/0440/1509/1870/files/bachelor_party_invitation_cards_templates.pdf
    • https://cdn.shopify.com/s/files/1/0428/4783/0183/files/ketevusipojosa.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_off000048a5.bin
a65b0271d2a6f45532907011f859ef80548e02a84b19a04cd3922e13aba4486d
pdf-font-stream PDF embedded font (sfnt) at offset 0x48A5 5044 bytes
font_01_sfnt_off00005997.bin
7bedb474f4bda2aa05cb5473673427f3f67ed389c5fe0625564c5752a5377085
pdf-font-stream PDF embedded font (sfnt) at offset 0x5997 10264 bytes
font_02_sfnt_off00007b2e.bin
a542ec26cea93e049a2e27cd59b1347dd9bbdea13775fd7b822b3c2b3136116f
pdf-font-stream PDF embedded font (sfnt) at offset 0x7B2E 4324 bytes