Malicious PDF — malware analysis report

Static analysis result for SHA-256 3dae755c945123a1…

MALICIOUS

PDF

43.1 KB Created: 2020-08-29 06:09:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 2ceb4645069c693b38a3da9f8090d8b2 SHA-1: 8e23b43be74f64137ca7ecca65fa605ecced2cca SHA-256: 3dae755c945123a17170f7d55dda44dc0d9f674e9c3ab372734b9e4f1da89651
152 Risk Score

Malware Insights

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

The PDF contains a significant number of embedded links, many of which point to a link farm hosted on static.usrfiles.com. One critical heuristic identified a link to known malicious redirector infrastructure at ttraff.ru, which is likely the primary malicious payload delivery mechanism. The document body, though heavily obfuscated, contains text related to accounting textbooks, suggesting a lure for users searching for educational materials. The ML classifier 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/wix?keyword=horngren%2527s+accounting+the+financial+chapters+10th+edition+solution+manual
    • https://static.usrfiles.com/ugd/b8c837_f7e4f4d5199546d08fb6467e3b47e4c3.pdf
    • https://static.usrfiles.com/ugd/b8c837_14ff98af2433439eacffcc91ab3a4e19.pdf
    • https://static.usrfiles.com/ugd/b8c837_c7708f8e6d364c7ba73769a42caad4d2.pdf
    • https://static.usrfiles.com/ugd/b8c837_1c55765bbe5749f695c7ef89e18e9ac8.pdf
    • https://static.usrfiles.com/ugd/b8c837_d33abb047e1d4cc7adca1459c80b1f3d.pdf
    • https://static.usrfiles.com/ugd/b8c837_150f3557ebb9460486fd6a6afa461a1e.pdf
    • https://static.usrfiles.com/ugd/b8c837_cec5fffabf6c46e29bee0d0afaadb69c.pdf
    • https://static.usrfiles.com/ugd/b8c837_fde285ca2f0545b58b282b894a371ec7.pdf
    • https://static.usrfiles.com/ugd/b8c837_cec3761a84a447d7b0164214c1a47698.pdf
    • https://static.usrfiles.com/ugd/b8c837_35130c0df6dd4341b1707073b8656f67.pdf
    • https://static.usrfiles.com/ugd/b8c837_ab6db6c9077e43ccaa1105bdd32d337a.pdf
    • https://static.usrfiles.com/ugd/b8c837_8801ef0e5bec44738a311b88c4222d24.pdf
    • https://static.usrfiles.com/ugd/b8c837_bc33f0c83bc640a29c5b29795b381735.pdf
    • https://static.usrfiles.com/ugd/b8c837_1e40d65d06b045dbad098a693df33e26.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_off000066dd.bin
4a940eb3e1195f86bb69b76b6b89fccd5a79ab6022935db1756b930b64727141
pdf-font-stream PDF embedded font (sfnt) at offset 0x66DD 5760 bytes
font_01_sfnt_off00007a5e.bin
1e740209205f5b43c1d89e0bf41d6e5245d0835ca9599be859fb9178e6967fdd
pdf-font-stream PDF embedded font (sfnt) at offset 0x7A5E 10956 bytes