Malicious PDF — malware analysis report

Static analysis result for SHA-256 528ed26e6a06c7b8…

MALICIOUS

PDF

49.8 KB Created: 2020-09-05 00:28:42 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: fa19719b076526556eeceec68a291f9d SHA-1: 4ee738bde5a2340b8267bcc83370585bdbf19536 SHA-256: 528ed26e6a06c7b88e2c922d4e2005f1458c4849821458cab86e657868846d73
152 Risk Score

Malware Insights

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

The PDF contains a critical heuristic firing for a malicious redirector link, which is also present in the document body. The ML classifier strongly flagged this PDF as malicious. The primary attack vector appears to be a lure disguised as an educational worksheet answer key, directing users to a malicious URL. No scripts were extracted, and the document body is heavily obfuscated, but the presence of the malicious redirector is sufficient for a high-confidence assessment.

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.link/pify?keyword=exponents+and+scientific+notation+worksheet+answer+key
    • https://cdn.shopify.com/s/files/1/0429/3656/5923/files/32160504094.pdf
    • https://cdn.shopify.com/s/files/1/0437/1054/6070/files/learning_from_data_a_short_course.pdf
    • https://cdn.shopify.com/s/files/1/0434/2402/2677/files/90925196280.pdf
    • https://cdn.shopify.com/s/files/1/0464/7220/0342/files/neliga.pdf
    • https://cdn.shopify.com/s/files/1/0430/0151/2090/files/dujubopu.pdf
    • https://cdn.shopify.com/s/files/1/0438/8909/8907/files/lozomosazejamerotakado.pdf
    • https://cdn.shopify.com/s/files/1/0432/6470/4665/files/rss_feeds_cnn.pdf
    • https://cdn.shopify.com/s/files/1/0437/1080/8216/files/9555010418.pdf
    • https://cdn.shopify.com/s/files/1/0429/5881/5398/files/weather_in_wausau_wi.pdf
    • https://cdn.shopify.com/s/files/1/0428/2764/5084/files/cornbread_dressing_nutrition_information.pdf
    • https://cdn.shopify.com/s/files/1/0444/6437/3927/files/wusanawuja.pdf
    • https://cdn.shopify.com/s/files/1/0437/1690/3080/files/47965569203.pdf
    • https://cdn.shopify.com/s/files/1/0430/3526/3138/files/8124521721.pdf
    • https://cdn.shopify.com/s/files/1/0433/3935/0181/files/tonedonidirarupot.pdf
    • https://cdn.shopify.com/s/files/1/0434/5351/3880/files/tilde_symbol_android_keyboard.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_off00007baa.bin
03b624efa94d054d0cf105789427e06fa99f92e6df7bb5cfbf412a77f40f6de8
pdf-font-stream PDF embedded font (sfnt) at offset 0x7BAA 5496 bytes
font_01_sfnt_off00008e7c.bin
53eabe99c8a801a958a9f6deca376beb8fecab6fb7453dd82aefef39dc17ba4c
pdf-font-stream PDF embedded font (sfnt) at offset 0x8E7C 13660 bytes