Malicious PDF — malware analysis report

Static analysis result for SHA-256 f2803c940eda8f51…

MALICIOUS

PDF

84.7 KB Created: 2020-09-10 04:44:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 381ac61a21efb509b4721024b709bf66 SHA-1: 73cc00485ba93143625c4136aaea09d50e3b3a01 SHA-256: f2803c940eda8f5184d09d54a5519ec514b2b50c349132d8d9cd4fe60de2c1c0
152 Risk Score

Malware Insights

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

The PDF contains numerous links, including one pointing to a known malicious redirector at https://ttraff.ru/wb?keyword=ielts%20writing%20samples%20band%209%20pdf. This suggests a phishing or scam attempt, likely using the guise of IELTS writing samples to entice clicks. The ML classifier strongly supports the malicious nature of this PDF.

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/wb?keyword=ielts%20writing%20samples%20band%209%20pdf
    • https://static.usrfiles.com/ugd/b8c837_fcd8e38937a246e79aa2b37feac3b5cd.pdf
    • https://static.usrfiles.com/ugd/b8c837_2f46307689d54debacfec8c14670a98d.pdf
    • https://static.usrfiles.com/ugd/ee6770_6cbf98a938d1417fb7bde3d4e07ec047.pdf
    • https://static.usrfiles.com/ugd/bc0d1e_61445c31e00a4280ae9bc7c3ac813bae.pdf
    • https://cdn.shopify.com/s/files/1/0431/8268/6362/files/icivics_race_to_ratify_answer_key.pdf
    • https://cdn.shopify.com/s/files/1/0431/0928/6050/files/78773610803.pdf
    • https://cdn.shopify.com/s/files/1/0431/1800/2340/files/altitude_app_free_for_android.pdf
    • https://cdn.shopify.com/s/files/1/0433/3830/1594/files/c._o._p._the_recruit_nds.pdf
    • https://cdn.shopify.com/s/files/1/0430/9437/6599/files/fafabixa.pdf
    • https://cdn.shopify.com/s/files/1/0428/5480/9759/files/bosch_dishwasher_e25_error.pdf
    • https://cdn.shopify.com/s/files/1/0437/5596/2522/files/tap_titans_2_artifacts_max_level.pdf
    • https://cdn.shopify.com/s/files/1/0428/1594/6911/files/remasorukuwimanefiji.pdf
    • https://cdn.shopify.com/s/files/1/0439/4817/9611/files/92320934986.pdf
    • https://cdn.shopify.com/s/files/1/0433/0687/7080/files/80789229335.pdf
    • https://cdn.shopify.com/s/files/1/0430/9463/8749/files/fringe_benefit_statement.pdf
    • https://cdn.shopify.com/s/files/1/0435/1619/9064/files/jiwiwexedixotewusen.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_off00010fed.bin
6f1d9a9660701b71a4d74085b428e3b593133a6d29ddebb27d072e85a3d2e91f
pdf-font-stream PDF embedded font (sfnt) at offset 0x10FED 5688 bytes
font_01_sfnt_off00012335.bin
ef1b6b8f594e708f2eb8841da62b43a418d708baf740ce61662dc410fee6e838
pdf-font-stream PDF embedded font (sfnt) at offset 0x12335 10072 bytes