Malicious PDF — malware analysis report

Static analysis result for SHA-256 d23541d5b1f7b6df…

MALICIOUS

PDF

41.3 KB Created: 2020-09-05 02:58:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: edf2cf076eb003af7d3985ad53dc3a48 SHA-1: 6cfdc272b0843183ebc906b7115511e5b0565b89 SHA-256: d23541d5b1f7b6df78d645eb6b9faae5cb97c4cd1a77857f9e06e2bca2fb7bf1
152 Risk Score

Malware Insights

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

The PDF contains a prominent link to a malicious redirector, identified by the PDF_MALICIOUS_REDIRECTOR_LINK heuristic. The document body, though partially corrupted, contains text suggesting it is related to answers for a quiz or test, which is a common lure. The PDF also hosts a large number of external links, many pointing to PDFs on static.usrfiles.com, indicating a link farm strategy. The ML classifier strongly flagged this PDF as malicious.

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.link/wix?keyword=capitulo+7b+prueba+7b-+2+answers
    • https://static.usrfiles.com/ugd/0cd3a8_6633717c8c1d47ec95dd7df863ffdc76.pdf
    • https://static.usrfiles.com/ugd/b98abb_81f979d1b30b4d469924fb50fcc62562.pdf
    • https://static.usrfiles.com/ugd/b1b3ad_69a2134dde004d9991cb13102d1a71c6.pdf
    • https://static.usrfiles.com/ugd/9eb187_be61556a5b8f4d7e86d26e10bed494ed.pdf
    • https://static.usrfiles.com/ugd/d5cf39_e4fc663d0e28492388ad7d3fef7eea09.pdf
    • https://static.usrfiles.com/ugd/ec0012_0087a83b574241e0b78c6633de536d52.pdf
    • https://static.usrfiles.com/ugd/76dd3d_3fbf9cc18bed424eadd166c5014f8720.pdf
    • https://cdn.shopify.com/s/files/1/0437/7329/6789/files/zugofeleluzelitimuz.pdf
    • https://cdn.shopify.com/s/files/1/0435/5584/8355/files/software_deployment_plan_document_template.pdf
    • https://cdn.shopify.com/s/files/1/0437/9593/9488/files/aphorisms_of_hippocrates.pdf
    • https://static.usrfiles.com/ugd/7ae8b3_8244b574553a423a97ee771338ab55f0.pdf
    • https://static.usrfiles.com/ugd/ac72e0_5a619139c0854cd8861c4cbc124362df.pdf
    • https://static.usrfiles.com/ugd/d48fe3_02d86e58f6f74682a430a03b474bbb04.pdf
    • https://static.usrfiles.com/ugd/b8c837_2ec284379e554faf84c97e216abefd89.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_off000060b6.bin
63c95def3319337ea4f65891e055bea528f37b0335a332a9a9d4d4435ac2d622
pdf-font-stream PDF embedded font (sfnt) at offset 0x60B6 5192 bytes
font_01_sfnt_off00007281.bin
e7922a377fd89ae957b00f81743f975ec2f898a04818e8801d18c03d3bc6929e
pdf-font-stream PDF embedded font (sfnt) at offset 0x7281 11720 bytes