Malicious PDF — malware analysis report

Static analysis result for SHA-256 20b21e557fb5db6c…

MALICIOUS

PDF

42.4 KB Created: 2020-08-24 23:00:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 1ecd1d0c481ecc2d7586f721d86b4faa SHA-1: c53e2dd1136c7f66220eb381bdfcb853c27182ba SHA-256: 20b21e557fb5db6c3f942295bc66d13fa7e62d18b5d0ba43e1a0f39e21a451f7
152 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1059.001 PowerShell

The PDF contains a mass of external links, including a primary link to a known malicious redirector at ttraff.ru. The document body, though heavily obfuscated, contains the text 'Happy birthday song free for brother' and the malicious URL, suggesting a lure to trick users into clicking the link. The ML classifier strongly supports the malicious verdict.

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=happy+birthday+song+free++for+brother
    • http://files.skilledlearners.com/uploads/1/3/2/6/132681394/2003340.pdf
    • http://files.cathstonardtextilearts.com/uploads/1/3/0/8/130874058/5808339.pdf
    • http://files.averytruittdesigns.com/uploads/1/3/1/4/131438113/juwaxapuz_bowavuno_bibokovuxesefin_rejomad.pdf
    • https://cdn.shopify.com/s/files/1/0438/4597/6224/files/c_char_array_to_string.pdf
    • https://cdn.shopify.com/s/files/1/0428/9835/8432/files/vuxopikuxoxixu.pdf
    • https://cdn.shopify.com/s/files/1/0428/8829/8662/files/fopegelovobiwazavi.pdf
    • https://cdn.shopify.com/s/files/1/0430/2408/9242/files/56837737886.pdf
    • https://cdn.shopify.com/s/files/1/0428/3590/2631/files/92810881553.pdf
    • https://cdn.shopify.com/s/files/1/0434/1573/2381/files/gebuwidolunotizotuz.pdf
    • https://cdn.shopify.com/s/files/1/0435/3366/4408/files/nadavagofusakokipakeligus.pdf
    • https://cdn.shopify.com/s/files/1/0437/7001/9994/files/today_football_highlights.pdf
    • https://cdn.shopify.com/s/files/1/0431/6174/7605/files/42190880930.pdf
    • https://cdn.shopify.com/s/files/1/0463/3211/7147/files/33561863883.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_off000067b8.bin
19b86b2823d34f0ccb277260afad103342a7226a531b828ef142783e39107416
pdf-font-stream PDF embedded font (sfnt) at offset 0x67B8 5476 bytes
font_01_sfnt_off00007a4a.bin
cbc1ef1a4dc4fdbbdf8be99fc98fc6dfdd5d773fe50732478ec457f5a65bcdc1
pdf-font-stream PDF embedded font (sfnt) at offset 0x7A4A 10088 bytes