Malicious PDF — malware analysis report

Static analysis result for SHA-256 2b635dd77927a7b2…

MALICIOUS

PDF

40.6 KB Created: 2020-08-08 21:23:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: c4c5e9dce2717e5e8ce91dbc691a0e6f SHA-1: ddb065b0271ab9f2f43f310945f331dc4ed18990 SHA-256: 2b635dd77927a7b2e71a5f78b6457281533d7573cb9c4b08b726eaff70c5a43c
152 Risk Score

Malware Insights

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

The PDF contains a critical heuristic firing for a malicious redirector link, specifically `https://ttraff.ru/pify?keyword=ldc+16+sept+answer+key+pdf`. This URL is embedded within the document body, disguised as a link to an answer key. The presence of a large number of external PDF links, many hosted on shopify.com, suggests a link farm intended to obscure the malicious redirector. The ML classifier also 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.ru/pify?keyword=ldc+16+sept+answer+key+pdf
    • http://files.englewoodfencing.org/uploads/1/3/2/6/132695325/44f0616d36c0.pdf
    • http://files.artofbobhannah.com/uploads/1/3/1/1/131164130/vesivajitujolatasoke.pdf
    • http://files.arrisdesrosiers.com/uploads/1/3/0/7/130738704/xigatumik.pdf
    • http://files.caseyharvilla.com/uploads/1/3/2/7/132712214/vevuzupakaki.pdf
    • https://cdn.shopify.com/s/files/1/0432/1175/1588/files/62849936849.pdf
    • https://cdn.shopify.com/s/files/1/0436/6172/1765/files/dekiziradidepepikasilete.pdf
    • https://cdn.shopify.com/s/files/1/0430/7327/4018/files/romijaj.pdf
    • https://cdn.shopify.com/s/files/1/0432/6365/6099/files/budilepeniximomamar.pdf
    • https://cdn.shopify.com/s/files/1/0438/4056/9494/files/91516213166.pdf
    • https://cdn.shopify.com/s/files/1/0431/6617/1287/files/78351897264.pdf
    • https://cdn.shopify.com/s/files/1/0435/3871/0696/files/tojil.pdf
    • https://cdn.shopify.com/s/files/1/0438/1101/2770/files/10441771027.pdf
    • https://cdn.shopify.com/s/files/1/0429/8774/9525/files/jumirosome.pdf
    • https://cdn.shopify.com/s/files/1/0433/9076/3175/files/mozekipifamu.pdf
    • https://cdn.shopify.com/s/files/1/0429/5147/5351/files/6526718247.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_off00005e79.bin
33b9bba107b18c3711bd7ec8a576bfd21a89c88ae060daee23c3ccc681347255
pdf-font-stream PDF embedded font (sfnt) at offset 0x5E79 5524 bytes
font_01_sfnt_off00007174.bin
102cbfd55946b2a8619d683c2f71a4d23fcfbe5538927456b5689a48dcc9b7d5
pdf-font-stream PDF embedded font (sfnt) at offset 0x7174 10156 bytes