Malicious PDF — malware analysis report

Static analysis result for SHA-256 28a762692523eda3…

MALICIOUS

PDF

45.0 KB Created: 2020-08-07 04:18:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 127a8eb54a2b8664aa9c5f4f2e139553 SHA-1: dcd983f1e4c108c08a952e39d1ff2401665d6a61 SHA-256: 28a762692523eda32f60db95ac2f7509fd4bbb10e0e485667bb05342164c9d16
152 Risk Score

Malware Insights

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

The PDF contains a critical heuristic firing indicating a malicious redirector link, specifically `https://ttraff.cc/pify?keyword=cds+exam+syllabus+pdf+file+download`. This URL is presented within the document body, disguised as a syllabus download, aiming to trick the user into clicking it. The presence of numerous other PDF links, many hosted on Shopify, suggests a link farm designed to improve SEO for malicious content. 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.cc/pify?keyword=cds+exam+syllabus+pdf+file+download
    • http://files.infantswimoviedo.com/uploads/1/3/1/4/131454109/5435244.pdf
    • http://files.chrishenkaline.com/uploads/1/3/2/7/132712139/lotenaxanokofujibes.pdf
    • http://files.aimhealthgta.com/uploads/1/3/1/6/131607630/5110791.pdf
    • https://cdn.shopify.com/s/files/1/0433/3859/6511/files/xuzoragizifi.pdf
    • https://cdn.shopify.com/s/files/1/0432/9691/5621/files/75596488322.pdf
    • https://cdn.shopify.com/s/files/1/0440/7987/4213/files/60401615895.pdf
    • https://cdn.shopify.com/s/files/1/0429/3532/0735/files/63389525161.pdf
    • https://cdn.shopify.com/s/files/1/0430/7442/0890/files/32126227787.pdf
    • https://cdn.shopify.com/s/files/1/0431/7364/2406/files/reduce_mp4_file_size.pdf
    • https://cdn.shopify.com/s/files/1/0437/3771/0744/files/74811916656.pdf
    • https://cdn.shopify.com/s/files/1/0429/0809/0535/files/47122352196.pdf
    • https://cdn.shopify.com/s/files/1/0431/0378/1015/files/kikorupu.pdf
    • https://cdn.shopify.com/s/files/1/0433/3725/3023/files/sceptre_tv_codes.pdf
    • https://cdn.shopify.com/s/files/1/0431/9520/3745/files/kevawovazutadixaman.pdf
    • https://cdn.shopify.com/s/files/1/0435/5381/6728/files/gabesejonilimusiberawala.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_off000071f2.bin
0d5699c1b6f65b85cca9343be50256e9a0e7933d5d3dddc71169aefe29bd6ac0
pdf-font-stream PDF embedded font (sfnt) at offset 0x71F2 5400 bytes
font_01_sfnt_off00008453.bin
47031b0d2673d38b3f4481e25860f5b07eac22eee3daa3342993cb8b498f406d
pdf-font-stream PDF embedded font (sfnt) at offset 0x8453 10128 bytes