Malicious PDF — malware analysis report

Static analysis result for SHA-256 91cc4d11d93ef30e…

MALICIOUS

PDF

45.9 KB Created: 2020-09-01 09:06:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: eda5ebdc011e288f865bbc4a061221ea SHA-1: b1e33789f2032efce8740743097ff267d1692214 SHA-256: 91cc4d11d93ef30eee55dfa78b97c7c00585f69352b65d7b325169dbfe585eb9
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.cc, disguised with a keyword related to educational marks. The document body, though heavily obfuscated, contains this URL and references to educational content, reinforcing the lure. The presence of numerous links to static.usrfiles.com, while marked as benign, suggests a link farm used for SEO poisoning to attract victims searching for specific documents. 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.cc/wix?keyword=cbse+improvement+exam+marksheet+2018
    • https://static.usrfiles.com/ugd/1fbf8b_05919bdd06ff47899632d0262db2cf4b.pdf
    • https://static.usrfiles.com/ugd/3be3a7_2c8c4ea4326b453ea5dfbe017974a089.pdf
    • https://static.usrfiles.com/ugd/b8c837_7e4e60300a364766892853ec9bd7eabb.pdf
    • https://static.usrfiles.com/ugd/8cbfce_139e33df894f4cb6b32af181de057357.pdf
    • https://static.usrfiles.com/ugd/930050_a64854df27e642d78484fd0dbcb233d9.pdf
    • https://static.usrfiles.com/ugd/04e6f9_9fbcd2a39a114b9ab03427aec038ea97.pdf
    • https://static.usrfiles.com/ugd/b8c837_06be2f7c8e9b444bb602d682ebe931fd.pdf
    • https://static.usrfiles.com/ugd/7041e4_ed355b9c7fe445d281eb4b8ae0a9d799.pdf
    • https://static.usrfiles.com/ugd/b8c837_f3f4a0e144e5436d86d7252bc50e2254.pdf
    • https://static.usrfiles.com/ugd/ae15ca_cde00a31523d45dcb29458eb10edba1b.pdf
    • https://static.usrfiles.com/ugd/b8c837_ecdd369a514c4b62820ed775c77ba857.pdf
    • https://cdn.shopify.com/s/files/1/0462/7487/1458/files/rirasudeviwofasetagefad.pdf
    • https://cdn.shopify.com/s/files/1/0433/8014/6339/files/lilimumogabojedovule.pdf
    • https://cdn.shopify.com/s/files/1/0430/4253/7629/files/pekogikijatilowezemaviren.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_off0000731b.bin
761d71fdd1a081848ea45faed4143c6e275b361add383d8d0529fc739c7deba6
pdf-font-stream PDF embedded font (sfnt) at offset 0x731B 5784 bytes
font_01_sfnt_off000086a4.bin
1aa4cca293792e2b9141cd1fbb029a70b6aa7c53a97b12b315e23761a0c2583d
pdf-font-stream PDF embedded font (sfnt) at offset 0x86A4 10796 bytes